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IntroductionUtility Programs for DRAINSGeoffrey O'LoughlinAnstad Pty LtdMarch 2008This collection of spreadsheet utilities can be applied to create inputs for the DRAINS Program (www.watercom.com.au).DRAINS can accept a number of inputs from spreadsheets, such as rainfall intensity patterns, detention basin elevation-storagerelationships, weir characteristics and hydrographs.Some of the procedures set out here may be eventually in corporated into DRAINS, but most are more easily implemented and variedusing the capabilities of Excel.DisclaimerThese worksheets are supplied to users of the DRAINS program by Anstad Pty Ltd on the basis that they will check the validityof the results obtained and the methods used. Tests can be made by varying the program inputs and inspecting cell formulae.Anstad Pty Ltd does not accept liability for loss or damage of any kind claimed to arise either directly or indirectlyfrom use of this spreadsheet.INDEXThe following worksheets are provided in this version:Under the 'Rainfalls' Tag:1. Worksheet Calculating Intensities from Australian Rainfall & Runoff 1977 Polynomials2. Worksheet Calculating Probable Maximum Precipitation Patterns from Bureau of Meteorology (2003)3. Worksheet Setting Up Embedded Design Storms4. Temporal Patterns for Gold Coast City Council AreaUnder the 'Ponding' Tag:Worksheet defining Ponded Volumes at Sag Pits for use in DRAINSUnder the 'Basin Areas' Tag:Worksheet Calculating Elevation-Surface Area Relationships for Detention Basins of Certain ShapesUnder the 'Weirs' Tag:1. Worksheet Calculating an Elevation-Discharge Relationship for a Series of Weirs2. Worksheet Calculating an Elevation-Discharge Relationship for a Parabolic WeirUnder the 'Orifices' Tag:Worksheet Calculating an Elevation-Discharge Relationship for a Circular Orifice or for Multiple OrificesUnder the 'Pumping' Tag:Worksheet Establishing a Pumping Curve Relationship for use with DRAINSUnder the 'Tailwater' Tag:Worksheet Setting Time-Varying Tailwater Levels

RainfallsFour sheets are provided here.1. Worksheet Calculating Intensities from Australian Rainfall & Runoff 1977 PolynomialsEnter the 49 required factors in the table below. Results appear in the green cells.ARIFactors(years)ABCDEFG12.5841-0.5792-0.01320.00935-0.001792-0.00042200.0000784This is an obsolete method for calculating22.8558-0.5853-0.01450.00817-0.001339-0.00027540.0000419rainfall intensities using polynomial equations.53.1293-0.6054-0.01330.00776-0.001225-0.00014590.0000198While it was superseded by another method103.2768-0.6162-0.01300.00716-0.001019-0.0000301-0.0000060in the 1987 Australian Rainfall & Runoff, it is203.4463-0.6254-0.01300.00677-0.0008550.0000469-0.0000220still widely used, and the parameters A to G503.6459-0.6362-0.01310.00596-0.0005700.0001824-0.0000531are still available on information provided by the1003.7837-0.6435-0.01300.00542-0.0004150.0002791-0.0000733Bureau of Meteorology.DurationAverage Recurrence Interval (years)(minutes)125102050100544.259.281.897.6118.4148.9174.1641.455.376.491.1110.4138.8162.3739.052.171.885.5103.6130.0152.0837.049.467.980.797.6122.3142.9935.247.064.476.592.4115.7135.01033.744.961.472.887.9109.8128.01231.141.356.366.680.299.9116.31528.037.150.359.371.388.5102.82024.332.143.250.860.875.287.12521.628.538.244.753.565.976.23019.625.834.540.248.059.168.13518.023.731.536.743.753.761.94016.722.029.133.940.349.556.94515.620.527.231.637.546.052.95014.719.325.529.635.243.049.45513.918.324.127.933.140.546.5minutes6013.317.422.926.531.438.344.0hours1.510.513.717.920.624.329.633.828.811.515.017.220.324.528.037.09.111.713.415.718.921.545.97.69.811.213.115.717.864.66.07.68.710.112.113.793.64.76.06.87.99.410.6123.13.95.05.76.67.88.9182.43.13.94.45.16.16.9242.02.53.23.74.35.15.8361.51.92.52.83.33.94.5481.21.62.02.32.73.33.7601.01.31.72.02.32.83.2720.91.21.51.72.02.52.82. Worksheet Calculating Probable Maximum Precipitation Patterns from Bureau of Meteorology (2003)A developed version of the method given in previous Bulletins 51 and 53 is available for download from www.bom.gov.au/hydro/has/gsdm_document.shtmlThis procedure only determines the rainfall patterns. It does not apply the spatial distribution procedure described in Section 6 of the document.FOLLOW THE PROCEDURES BELOW, ENTERING VALUES IN THE YELLOW BOXES.1. Use one of the procedures below to determine probable maximum precipitation depths for various durations.If area >= 1 km2,Catchment Area (km2)2DurationSmoothRoughAveragedAdjustedRoundedPercent Rough (%)25Section 4.2(h)DepthDepthDepthDepthDepthElevation of Catchment (m)50Section 4.3(mm)(mm)(mm)(mm)(mm)Moisture Adjustment Factor (%)67Figure 30.250000.50000.7500010001.500020002.50003000400050006000Enter depths from Figure 4If area < 1 km2,for the particular catchment area.Check - Depths taken from Figure 4Point1 km2Point1 km2Catchment Area (km2)1DurationSmoothRoughAveragedAdjustedRoundedValueValueValueValuePercent Rough (%)25Section 4.2(h)DepthDepthDepthDepthDepth(Smooth)(Rough)(Rough)Elevation of Catchment (m)50Section 4.3(mm)(mm)(mm)(mm)(mm)(mm)(mm)(mm)Moisture Adjustment Factor (%)67Figure 30.252452452451641602502452502450.53503503502352303603503603500.7544044044029529046044046044015105105103423405705105705101.558065559940140064058074065526477706784544507106478807702.56908527314894907606909908523722938776520520810722109093847931065861577580900793125010655856117693662763096085613601176690012429866606601000900145012422. Transfer the results from eitherNote: Depths are calculated from those in Bulletin 53of the above procedures tocorresponding to zero area and to 1 km2.the coloured columns below.AdjustedDepth3. The intensities in the coloured columns given below can be transferred directly to the rainfall data base in DRAINS.(mm)Using your mouse, select the numbers in the pairs of columns required and choose Copy from the View menu.160Go to the DRAINS rainfall data base using the Project -> Rainfall Data option in DRAINS. Click the Add a New Storm button.230When the new window appears, click the Paste button. The numbers and accompanying graph will appear. Enter a suitable title.290Repeat the process as required.34040015 Minute Pattern30 Minute Pattern45 Minute Pattern60 Minute Pattern450TimeIntensitiesPercentagesTimeIntensitiesPercentagesTimeIntensitiesPercentagesTimeIntensitiesPercentages490(minutes)(mm/h)(%)(minutes)(mm/h)(%)(minutes)(mm/h)(%)(minutes)(mm/h)(%)5200845440552200418120326858057303856622455921754901263010346181055220105221510490126601515497181548714154901220331122045213204491125166625383112540810303031393036793520963532684010434028674545204550163455822601.5 Hour Pattern2 Hour Pattern2.5 Hour Pattern3 Hour PatternTimeIntensitiesPercentagesTimeIntensitiesPercentagesTimeIntensitiesPercentagesTimeIntensitiesPercentages(minutes)(mm/h)(%)(minutes)(mm/h)(%)(minutes)(mm/h)(%)(minutes)(mm/h)(%)024050252140196100166853367153241815294151525012103848303061730274143025012154329452701545255134525012203848602521460235126022911253367751981175216117520810303367901267901961090187935336710572410513771051668402886120120985120146745288613559313510455028861501508345528861654226024051806519247014437514438096285481904 Hour Pattern5 Hour Pattern6 Hour PatternTimeIntensitiesPercentagesTimeIntensitiesPercentagesTimeIntensitiesPercentages(minutes)(mm/h)(%)(minutes)(mm/h)(%)(minutes)(mm/h)(%)01396010140106415186815151615106430232103020283015864520994517674515866020996017676015867518687517677515869018689017679015861051627105176710515861201627120151612015861351396135151613513251501396150126515013251651165165126516513251809341801265180132519570319512651951325210462210101421010642254622257632251064240240763240793255502255793270502270793285251285532300300532315532Note: The method can only be used for durations up to 3 hours330261over a large part of southern and central Australia, including South Australia,345261western NSW and western Victoria - see Figure 2 of the Bulletin.3603. Worksheet Setting Up Embedded Design StormsThe applicability of the design rainfall patterns in Australia Rainfall and Runoff has been questioned by Phillips (1995), Rigby and Bannigan (1996) and Rigby et al (2003),who have suggested that rainfall burst patterns be embedded into longer patterns of the same ARI, to allow for rainfall occurring before the design burst.This section shows an example of an embedded storm, and provides the numerical percentage data specifying the patterns applying to the eight zones of Australiashown in Figure 3.2 of Australian Rainfall and Runoff (1987). It is not possible to provide a general procedure because many combinations of times steps andstorm durations are involved Those wishing to use this procedure will need to set up their own cells in the same way as shown in the example. Percentage rainfallsare provided for all zones.References:Phillips, B.C. (1995) Drainage Design Practice for Land Development - Rational Formula Procedures, 2nd International Symposium on Urban Stormwater Management, Institution of Engineers, Australia, MelbourneRigby, E.H. and Bannigan, D.J. (1996) The Embedded Design Storm Concept - A Critical Review, 23rd Hydrology and Water Resources Symposium, Institution of Engineers, Australia, HobartRigby, T., Boyd, M., Roso, S., VanDrie, R. (2003) Storms, Storm Bursts and Flood Estimation, A Need for Review of the AR&R Procedures, 28th Hydrology and Water Resources Symposium, Institution of Engineers, Australia, WollongongThe following example shows a 1 hour storm embedded in a 9 hour duration pattern.1 hour intensity (mm/h)999 hour intensity (mm/h)25.4Total Depth (mm)99Total Depth (mm)228.6Depth of Highest 1 Hour (mm)71.5518Correction Factor0.82522435791. Set out the 9 hour2. Locate the 1 hour pattern overpattern using the shorterthe highest 1 hour part of the3. Select the orange columns belowtime step for the 1 hour9 hour pattern, and scale otherand transfer to the rainfall databasepattern.depths by the correction factor.in DRAINS.OriginalAdjustedAdjusted9 hour1 hour9 hour9 hourRainfallRainfallRainfallRainfallPeriodTimeDepthsDepthsDepthsTimeIntensities(minutes)(mm)(mm)(mm)(minutes)(mm/h)103.312.74032.82253.312.74532.823103.312.741032.824153.312.741532.825203.312.742032.826253.312.742532.827304.574.264.263051.088354.577.237.233586.729404.5715.9415.9440191.2710454.5711.4811.4845137.8111504.5721.4821.4850257.8012554.579.909.9055118.8013607.358.918.9160106.9214657.355.945.946571.2815707.355.155.157061.7816757.353.473.477541.5817807.352.972.978035.6418857.352.282.288527.3219901.521.269015.0920951.521.269515.09211001.521.2610015.09221051.521.2610515.09231101.521.2611015.09241151.521.2611515.09Base Data:251201.371.1312013.58261251.371.1312513.58Percentage Rainfall Depths for Zone 1, South-East Coast Division and Tasmania, ARI 30 years602951.180.9729511.70613002.742.2630027.17Duration (minutes)51015202530456090120180270360540720108014401800216028804320623052.742.2630527.17Time Step (minutes)555555555515153030306060120120120240633102.742.2631027.17Period643152.742.2631527.17110054332018165.34.33.52.45.71.64.12.41.61.50.61.30.22.62.7653202.742.2632027.172464740262413.97.35.95.216.85.486.34.53.41.53.31.33.63.4663252.742.2632527.1732030353023.316.113.93.323.49.8114.43.52.41.54.32.52.66673304.193.4633041.50410111017.711.684.98.77.623.34.51.64.42.57.23.54.63.7683354.193.4633541.50510129.821.7109.111.817.815.33.40.66.34.44.36.23.624.8693404.193.4634041.506811.71019.55.27.812.98.110.52.66.31.515.35.16.67.9703454.193.4634541.5077.995.516.75.84.772.82.618.42.58.17.69.912.8713504.193.4635041.5086.565.411.96.73.474.74.763.49.99.43.14.8723554.193.4635541.5093.95.24.55.34.86.85.17.43.612.93.522.421.3139.9733601.221.0136012.07103.53.53.33.85.66.117.62.686.612.61519.40.2743651.221.0136512.071134.53.42.84.53.113.13.6108.75.211.27.71.6753701.221.0137012.07122.33.64.31.93.71.96.575.415.82.34.54.60.2763751.221.0137512.07132.44.33.85.49.24.510.92.34.55.717.5773801.221.0138012.07142.62.42.73.515.82.53.41.33.51.61.7783851.221.0138512.07152.62.43.82.43.53.54.40.21.31.70.7793900.880.723908.68161.63.42.72.50.61.54.61.32.70.7803950.880.723958.68171.52.41.61.34.81.56.71.41.60.7814000.880.724008.68181.51.21.61.311.31.55.60.20.60.7824050.880.724058.68191.262.51.6834100.880.724108.68202.54.93.51.6844150.880.724158.68211.21.62.50.4854200.720.604207.17221.32.71.40.4864250.720.604257.17231.30.61.50.4874300.720.604307.17241.40.50.50.4884350.720.604357.17894400.720.604407.17Total100100100100100100100100100100100100100100100100100100100100100904450.720.604457.17914500.570.474505.66924550.570.474555.66Percentage Rainfall Depths for Zone 2, Murray-Darling Division, ARI 30 yearsDuration (minutes)51015202530456090120180270360540720108014401800216028804320Time Step (minutes)555555555515153030306060120120120240Period110054332018165.34.34.42.39.35.37.57.27.315.89.617.716.214.816.32464740262413.97.312.1617.614.628.423.611.625.222.829.528.626.632.632030353023.316.119.312.127.921.81713.820.75.914.111.59.18.68.6410111017.711.67.76.610.69.210.58.57.97.26.96.97.95.46.4510129.821.710.116.378.49.54.54.595.13.63.44.66.46811.7105.98.96.165.23.63.54.34.19.16.73.95.377.997.55.35.366.34.15.711.76.55.74.84.54.186.565.75.14.54.54.53.23.25.14.43.84.24.23.193.95.254.33.83.93.72.32.82.91.93.13.43.51.8103.53.83.43.23.53.16.32.61.63.42.62.932.61133.34.32.62.82.37.34.61.92.82.12.52.61.4122.333.82.13.125.43.60.92.11.82.22.21.5132.83.22.32.83.93.52.51.21.61.42.2142.52.82.22.22.62.43.80.81.31.71.5152.22.61.91.51.91.31.50.61.41.91.61622.11.71.72.50.71.71.31.31.4171.52.11.51.12.30.411.31.31.6181.21.81.30.91.80.20.81.21.21.6191.71.61.41.4201.51.11.11.2211.41.50.91.2221.110.71.2230.91.10.41.2240.40.70.51.1Total100100100100100100100100100100100100100100100100100100100100100Percentage Rainfall Depths for Zone 3, North-East Coast Division, ARI 30 yearsDuration (minutes)51015202530456090120180270360540720108014401800216028804320Time Step (minutes)555555555515153030306060120120120240Period110054332018165.34.34.12.74.22.54.98.743.411.91.923.319.825.82464740262413.97.36.8415.69.615.4128.621.519.525.36.110.54.732030353023.316.18.6611.112.622.819.317.93.984.27.26.11.7410111017.711.654.221.416.45.443.92.66.85.12.20.80.7510129.821.711.710.296.912.33.66.44.551.13.71.31.36811.7105.84.28.46.794.712.511.12.93.63.10.92.677.9914.712.67.35.986.22.11.90.81.51.40.71286.569.98.45.43.95.32.221.22.12.30.91.11793.95.25.376.33.56.25.42.68.83.22.91.31.66103.55.14.34.74.74.23.14.47.11.19.32.64.53.11134.74.43.75.33.67.23.32.21.57.50.871122.32.742.95.92.9116.51.51.216.11.72.52.1133.83.74.33.24.95.23.61252.97.5143.43.43.22.3314.84.56.415.32.29.4153.13.12.81.92.96.14.10.811.68.63.8162.32.72.31.51.832.39110.5171.831.92.41.80.81.34.35.20.5181.22.81.61.33.70.460.51.80.3192.12.38.13.9201.61.41.81.52121.22.61.3221.51.30.73.5231.30.90.60.7240.80.60.40.6Total100100100100100100100100100100100100100100100100100100100100100Percentage Rainfall Depths for Zone 4, Timor Sea and Gulf of Carpenteria Divisions, ARI 30 yearsDuration (minutes)51015202530456090120180270360540720108014401800216028804320Time Step (minutes)555555555515153030306060120120120240Period110054332018165.34.32.82.55.54.512.48.69.526.423.629.126.723.625.82464740262413.97.38.84.917.99.225.923.322.316.614.114.712.910.39.632030353023.316.112.79.922.314.619.115.99.75.46.77.45.44.21.7410111017.711.69.811.613.5198.97.36.79.95.34.952.41.6510129.821.710.98.110.211.77.74.74.45.63.82.83.21.41.76811.7108.28.98.46.36.16.23.45.13.421.81.53.977.996.66.86.86.65.14.92.84.83.51.91.91.39.686.567.15.14.55.54.24.563.22.52.11.81.67.593.95.25.75.73.63.93.543.72.42.12.11.90.62.1103.55.24.53.13.433.53.32.71.93.12.32.21.81134.64.52.42.82.33.23.12.123.52.94.62.3122.34.14.21.82.51.82.62.61.91.64.12.62.24.9133.33.52.22.92.840.77.55.25.311.4143.73.81.82.22.820.38.97.26.96.1152.231.722.41.91.75.998.51.9161.82.91.61.52.22.22.44.33.32.1171.52.21.51.41.922.13.81.83.418121.21.31.91.82.22.11.72.6191.91.82.81.5201.41.63.31.72111.72.92.6221.20.443.7230.31.84.44.2240.11.22.72.9Total100100100100100100100100100100100100100100100100100100100100100Percentage Rainfall Depths for Zone 5, Lake Eyre and Western Plateau Divisions, ARI 30 yearsDuration (minutes)51015202530456090120180270360540720108014401800216028804320Time Step (minutes)555555555515153030306060120120120240Period110054332018165.34.37.33.78.96.210.6129.525.523.9302825.131.32464740262413.97.310.56.323.61826.123.621.112.211.415.813.510.611.732030353023.316.116.410.417.413.716.97.86.57.93.9107.96.48410111017.711.69.312.212.410.68.974.47.19.37.2766.6510129.821.78.48.77.98.286.66.46.15.66.75.556.46811.7106.47.26.84.56.764.45.84.764.85.44.977.995.75.95.85.45.65.74.74.64.554.54.43.786.565.25.357.34.75.24.45.33.74.23.73.82.693.95.24.75.34.14.33.64.744.23.53.52.733.1103.53.94.83.43.44.12.93.73.52.72.83.12.62.31134.24.52.83.12.62.533.732.32.222122.33.441.93.82.23.73.332.622.22.12132.53.833.62.432.21.52.31.82.3141.93.12.64.42.92.62.21.62.51.52.4152.23.32.11.41.92.11.61.42.41.62.5163.82.11.61.12.71.61.12.61.72.7172.92.11.31.11.711.92.51.92.8181.32.70.90.71.80.82.12.622.7191.52.71.82.1200.91.51.22211.31.61.72.1220.71.71.72.2230.11.81.82.3240.11.91.92.4Total100100100100100100100100100100100100100100100100100100100100100Percentage Rainfall Depths for Zone 6, South Australian Gulf Division, ARI 30 yearsDuration (minutes)51015202530456090120180270360540720108014401800216028804320Time Step (minutes)555555555515153030306060120120120240Period110054332018165.34.33.21.86.11.94.367.36.711.213.312.115.818.22464740262413.97.33.512.326.914.87.825.523.225.823.930.429.12733.632030353023.316.15.116.11821.426.94.72.6128.718.517.711.112.1410111017.711.67.15.712.65.117.215.814.716157.38.97.58510129.821.719.33.49.510.912.510.8103.25.39.76.35.866811.7108.79.87.58.69.88.25.82.26.75.44.15.13.977.99116.8576.44.74.49.14.34.25.33.1586.5614.38.34.33.95.23.94.64.33.82.43.54.8393.95.25.94.93.54.53.62.73.85.33.63.22.73.81.7103.52.82.72.95.92.81.92.8331.82.22.62.311343.12.23.42.13.72.42.42.11.31.72.10.9122.34.63.91.52.21.41.51.721.811.31.21.4132.44.42.92.32.11.62.50.711.81.1141.42.62.53.23.31.71.60.51.21.50.7151.721.61.31.91.50.90.30.80.90.7162.22.31.41.71.61.21.40.91.10.3171.91.51.11.21.41.11.20.710.7180.92.10.90.91.30.90.80.50.70.4191.710.60.7201.31.10.50.6211.10.80.50.42210.700.3230.70.90.20.5240.50.60.40.6Total100100100100100100100100100100100100100100100100100100100100100Percentage Rainfall Depths for Zone 7, Indian Ocean Division, ARI 30 yearsDuration (minutes)51015202530456090120180270360540720108014401800216028804320Time Step (minutes)555555555515153030306060120120120240Period110054332018165.34.364.24.458.74.13.613.812.531.530.727.632.52464740262413.97.311.79.816.313.123.619.718.325.824.66.969.81132030353023.316.113.511.921.318.311.98.712.47.75.815.914.85.37.5410111017.711.6107.512.38.416.44.93.83.98.77.16.35.35.5510129.821.75.94.19.66.48.13.22.710.56.47547.36811.7109.45.67.25.44.34.21.46.45.64.54.34.34.777.997.48.23.75.13.111.73.14.24.63.22.94.33.786.5644.265.13.87.14.832.52.55.12.62.393.95.24.54.18.64.65.88.610.2433.93.732.4103.55.44.15.24.16.95.87.72.642.82.72.42.51134.94.23.13.85.13.36.122.33.42.422.6122.33.63.82.33.72.33.23.23.40.65.53.23.63132.43.83.33.12.92.30.32.12.42.22.7141.73.53.21.92.82.121.92.11.92.1152.81.32.82.62.32.13.31.82.122.4162.42.12.82.32.72.32.122.12.5173.33.12.631.921.92.12.22.7181.12.92.32.621.90.32.22.42.6191.72.30.51.12011.51.82.2212.91.41.22.4223.30.722.4232.31.63.62.4240.40.60.42.5Total100100100100100100100100100100100100100100100100100100100100100Percentage Rainfall Depths for Zone 8, South-West Coast Division, ARI 30 yearsDuration (minutes)51015202530456090120180270360540720108014401800216028804320Time Step (minutes)555555555515153030306060120120120240Period110054332018165.34.35.82.111.96.49.112.611.413.111.69.912.911.7272464740262413.97.314.813.224.218.316.18.221.622.821.225.19.322.814.432030353023.316.111.49.916.1105.423.77.39.27.414.723.47.39.5410111017.711.69.67.15.98.225.354.44.46.47.975.77.5510129.821.77.15.56.812.1126.868.44.87.16.15.75.96811.7106.46.19.34.16.96.25.23.36.75.65.85.37.177.998.38.27.93.45.35.24.67.346.94.653.586.563.44.95.15.36.154.85.95.64.75.33.9593.95.24.433.76.14.64.64.23.43.722.61.62.1103.54.72.64.24.43.53.22.33.74.12.51.71.72.51133.93.62.93.53.12.82.54.93.33.42.92.72.9122.33.63.521.52.62.32.12.92.91.73.41.90.9135.32.623.93.62.32.62.94.41.41.4142.42.12.71.73.32.62.34.13.84.51.21523.13.22.12.91.92.11.51.82.11.4162.93.45.33.62.71.41.91.334.2172.84.22.31.61.91.41.62.31.51.9181.241.21.51.61.11.11.42.51.6194.50.71.51.2202.41.80.53.3211.61.70.91.2221.21.21.61.3230.81.311.3240.40.91.21.4Total1001001001001001001001001001001001001001001001001001001001001004. Temporal Patterns for Gold Coast City Council AreaThese are taken from Attachment 3.5D in Section 3.5 of the Gold Coast City Council Land Development Guidelines (2005).They differ from the Australian Rainfall and Runoff patterns.5 Minute Pattern10 Minute Pattern15 Minute Pattern20 Minute PatternPercentage Rainfall Depths for Gold Coast City Council Area, ARI 30 yearsARI (years)1ARI (years)1ARI (years)1ARI (years)1Intensity100Intensity100Intensity100Intensity100Duration (minutes)51015202530456090120180270360540720108014401800216028804320(mm/h)(mm/h)(mm/h)(mm/h)Time Step (minutes)555555555515153030306060120120120240TimeIntensitiesTimeIntensitiesTimeIntensitiesTimeIntensitiesPeriod(minutes)(mm/h)(minutes)(mm/h)(minutes)(mm/h)(minutes)(mm/h)110045.1332216.214.67.65.13.52.55.48.253.32.33.23.13.32.32.35.502.902.004.408.5254.939.632.52824.610.584.93.214.56.45.53.90.32.20.42.91.31.82.754.452.61516.5156.2327.426.622.920.611.49.485.518.54.96.61.81.21.51.72.51.71.94108.3105.53023.0304.4418.919.117.219.712.38.211.210.17.210.12.824.40.83.82.62.16.1159.01514.34510.8457.2513.812.516.511.713.19.77.55.318.44.72.94.72.3433.14.12016.52011.4607.0604.8610.512.81711.36.26.85.78.34.337.24673.332513.1256.7756.1755.478.78.76.676.14.314.25.73.511.14.86.24.12.311.6306.6307.9905.2903.686.776.45.97.38.57.46.84.314.75.59.84.83.615356.3356.11057.01059.396.16.26.14.61014.16.19.34.75.748.962.820405.8404.512010.212017.7105.65.64.15114.59.34.37.6518.13.83.96.4455.1453.91353.913512.7114.64.33.74.74.69.813.94.97.16.712.616.73.73.6503.7503.51503.31504.0124.44.73.64.13.24.16.89.55.67.17.410.55.53.1554.1553.21652.61652.6133.93.42.95.75.35.912.94.79.115.43603.3603.01801802.3143.23.12.75.111.85.14.1411.79.32.5652.6652.41952.11533.21.53.664.17.15.86.26.62.4702.4702.72101.4162.73.63.62.35.33.48.13.842.4752.1753.32252.9172.43.23.86.54.53.84.13.35.72.3802.0802.52403.2182.13.42.14.23.82.73.82.18.92.3851.8852.92551.7192.852.63.890902.2270202.62.73.24.1952.1212.23.22.42.61001.9221.83.22.11.11051.8231.83.22.11.11101.8241.73.12.11.11151.8120Total1001001001001001001001001001001001001001001001001001001001001006 Hour Pattern9 Hour Pattern12 Hour Pattern18 Hour PatternValues in red are assumed, as they are not given in the guidelines.ARI (years)1ARI (years)1ARI (years)1ARI (years)1Intensity100Intensity100Intensity100Intensity100(mm/h)(mm/h)(mm/h)(mm/h)TimeIntensitiesTimeIntensitiesTimeIntensitiesTimeIntensities(minutes)(mm/h)(minutes)(mm/h)(minutes)(mm/h)(minutes)(mm/h)03.902.601.802.5304.5303.2301.2601.8605.9601.7601.51201.49010.8902.3901.71803.712022.91204.11202.32404.11508.01503.71502.43007.518016.21805.41802.936012.82106.92107.12104.042018.52405.224010.82404.84805.32703.227010.22703.95408.43009.930017.53004.86007.13302.63306.933011.16605.23603605.23605.77205.83904.639014.97804.64202.94206.88403.44501.94505.59002.74806.44804.39603.15103.55103.310202.15405403.510805702.16002.66303.06603.06902.972024 Hour Pattern30 Hour Pattern36 Hour Pattern48 Hour PatternARI (years)1ARI (years)1ARI (years)1ARI (years)1Intensity100Intensity100Intensity100Intensity100(mm/h)(mm/h)(mm/h)(mm/h)TimeIntensitiesTimeIntensitiesTimeIntensitiesTimeIntensities(minutes)(mm/h)(minutes)(mm/h)(minutes)(mm/h)(minutes)(mm/h)02.402.401.701.7601.01202.01200.91201.41201.52401.62401.22401.51801.03602.93602.03601.62401.84803.24802.34802.53003.46005.56006.96002.73604.57205.97203.67201.84205.584010.68404.38403.04803.69609.19605.69602.25404.8108022.610803.210803.56006.8120014.5120020.912003.36607.913207.3132011.413205.472016.214404.014409.4144019.47803.715603.3156013.4156010.88407.516805.116806.016806.99009.4180018003.118003.79603.719202.619205.810203.220401.520409.810802.1216021603.311402.622803.912001.924002.012601.925201.313201.826401.313801.827601.21440288072 Hour PatternARI (years)1Intensity100(mm/h)TimeIntensities(minutes)(mm/h)05.32402.04803.57206.39603.812002.4144012.6168017.2192025.021606.324003.126402.628802.331201.833601.636001.538401.440801.34320

Rainfalls000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000

9 hour PatternAdjusted Pattern including 1 hour PatternPeriodRainfall Depths (mm)

PondingWorksheet defining Ponded Volumes at Sag Pits for use in DRAINSThis sheet is incomplete and is still subject to checking.DRAINS requires that a volume and a ponding depth be supplied for each sag pit.This sheet provides two methods for calculating ponded volumes.METHOD 1 - USING IRREGULAR TETRAHEDRON SHAPESThis covers two cases which should account for most ponding situations.At Pit A, flows come to a sag pit from two directions.The extent of ponding will depend on a number of factors relating to the geometry of the sag.The method below allows these to be altered, and defines volumes using equations developed in the paper,O'Loughlin, G.G., Darlington, D. and House, D. (1992) Mathematical Description of Pit Entry Capacities,I.E.Aust. International Symposium on Urban Stormwater Management, SydneyAt Pit B, the situation may be different because ponding occurs at a corner.This is not covered at present.Street DimensionsHeight ofLongitudinalLongitudinalDepth ofGutterHeight ofBuildingGrade toGrade toFootpathFootpathGutterStreetStreetLevelCrown aboveLine abovethe Leftthe RightWidthCrossfall(Kerb Height)WidthCrossfallGutterGutter(%)(%)(m)(%)(m)(m)(%)(m AHD)(m)(m)1.81.8420.128.5315.030.300.20Depth inGutterElevationVolume(m)(m AHD)(m3)0.0015.030.0Volume at Kerb Height (m3)1.10.0515.080.10.1015.130.6Volume at Road Crown (m3)19.60.1215.151.10.1515.182.1Volume at Building Line (m3)5.30.2015.235.30.2515.2810.90.3015.3319.6Volume = Volume on Roadway (2 irregular tetrahedrons (3-sided pyramids))0.3515.3831.8- Volume projected over crown0.4015.4347.5+ Volume on Footpath (2 irregular tetrahedrons)0.4515.4866.7- Volume projected over building line0.5015.5389.40.5515.58115.70.6015.63145.40.6515.68178.70.7015.73215.50.7515.78255.80.8015.83299.6

Basin AreasWorksheet Calculating Elevation-Surface Area Relationships for Detention Basins of Certain ShapesThis sheet demonstrates procedures for calculating surface areas for detention basins of various shapes, for use in the detention basin.calculations in DRAINS. For general areas, such as natural or smoothed landforms, it will be necessary to determine areas fromplanimeters, polygons in CAD drawings or routines in digital terrain models such as 12d or Civil 3D.Since DRAINS employs prismoidal calculations to determine detention basin volumes (as described in the DRAINS Help system).it is necessary to provide surface areas for eight or more horizontal slices keep errors in volumes within 1% for certain shapes.These include wedges and bowl-shaped storages with sides that slope more steeply as the elevation increases.The calculations below indicate how you can set up more complex calculations presenting elevation-storage relationships in two columns,from where they can be copied and pasted into the Detention Basin property sheet in DRAINS.WEDGE (Increasing Area)SQUARE AREA increasing according to y = B.x2SQUARE AREA increasing according to x = B.y2Elevation of Base (m AHD)122.5Elevation of Base (m AHD)41.1Elevation of Base (m AHD)52.9Rectangular Top Width (m)4.5Depth (or Height) (m)4.0Depth (or Height) (m)2.0Rectangular Top Length (m)10.0B in equation, y = B.x24.0B in equation, y = (x/B)0.50.4Depth (or Height) (m)1.2DepthElevationArea ofDepthWidthElevationArea ofDepthWidthElevationArea ofSlice(m)(m)StorageSlice(m)of Side(m)StorageSlice(m)of Side(m)Storage(m2)(m)(m2)(m)(m2)10122.5010041.1010052.9020.15122.75.62520.5241.6420.251.581138830153.22.530.3122.811.2531842.16430.52.236067977553.4540.45123.016.87541.51842.632440.752.738612787553.77.550.6123.122.5523243.11024513.162277660253.91060.75123.328.12562.55043.6250061.253.535533905954.212.570.9123.433.75737244.1518471.53.872983346254.41581.05123.639.37583.59844.6960481.754.183300132754.717.591.2123.74594.012845.11638492.04.47213595554.920CYLINDER with horizontal axisElevation (m AHD)16.7Radius (m)1.2Length (m)10.0DepthAngle withWidthElevationArea ofSlice(m)Centre(m)(m)Storage(radians)(m2)100016.70020.0750.35542120170.835164654416.788.351646544230.150.50536051031.161895003916.8511.618950038640.2250.62236848861.39910685816.9313.991068579650.30.72273424781.587450786617.0015.874507866460.3750.81275556141.742842505817.0817.428425057970.450.89566479391.873499399517.1518.734993995280.5250.97338991011.984313483317.2319.84313483390.61.04719755122.078460969117.3020.7846096908100.6751.1179797322.158124185517.3821.5812418549110.751.18639955232.224859546117.4522.2485954613120.8251.25297262292.27980262317.5322.7980262304130.91.31811607172.323790007717.6023.2379000772140.9751.38217994062.357435046817.6823.5743504683151.051.44546849562.3811761817.7523.8117617996161.1251.5082555652.395307913417.8323.953079134171.21.57079632682.417.9024181.2751.5082555652.395307913417.9823.953079134191.351.44546849562.3811761818.0523.8117617996201.4251.38217994062.357435046818.1323.5743504683211.51.31811607172.323790007718.2023.2379000772221.5751.25297262292.27980262318.2822.7980262304231.651.18639955232.224859546118.3522.2485954613241.7251.1179797322.158124185518.4321.5812418549251.81.04719755122.078460969118.5020.7846096908261.8750.97338991011.984313483318.5819.843134833271.950.89566479391.873499399518.6518.7349939952282.0250.81275556141.742842505818.7317.4284250579292.10.72273424781.587450786618.8015.8745078664302.1750.62236848861.39910685818.8813.9910685796312.250.50536051031.161895003918.9511.6189500386322.3250.35542120170.835164654419.038.3516465442More than 33 slices may be needed to maintain accuracy in this case.332.40019.100CYLINDER with sloping axisRadius (m)1.2Lowest Elevation of Invert "A" (m AHD)16.70This shape is quite complicated. Rather than calculating areas from truncated parabolic shapes,Length, L (m)10.0Highest Elevation of Invert "B" (m AHD)16.90this procedure calculates the water surface widths at the centre of the cylinder and at the ends,Slope, S0 (%)2.000Lowest Elevation of Obvert "C" (m AHD)19.10averages these and multiplies by the cylinder length. Potential errors can be reduced by takingHighest Elevation of Obvert "D" (m AHD)19.30shorter divisions between layers at the lowest and highest depths.Slope Angle, q (radians)0.019997334Slope Angle, q (degrees)1.1457628382Mid point height, hm (m)1.299740078CentreEquivalentDepthHalfLower EndDepthHalfCentreDepthHalfUpper EndArea ofDepthDepthAdjustedAngle withSurfaceAdjustedAngle withSurfaceAdjustedAngle withSurfaceElevationStorageSlice(m)(m)for SlopeCentreWidthfor SlopeCentreWidthfor SlopeCentreWidth(m)(m2)D1 (m)(radians)B1 (m)D1 (m)(radians)B1 (m)D2 (m)(radians)B2 (m)10000000000016.70020.0250.0250.02500499950.20450071550.487387930900000016.731.624626436430.050.050.0500099990.28971616270.685632547700000016.752.285441825540.10.10.1000199980.4111795590.95925803660.0000199980.00577322210.01385565600016.803.243712308850.20.20.2000399960.5857458371.32677050070.1000399960.41122125180.95934975810.0000399960.00816458030.01959477516.907.685716779660.30.30.3000599940.72280982991.58758682990.2000599940.58577598171.32683078710.1000599940.41126294050.959441469217.0012.912863620670.40.40.4000799920.84115810081.78899746320.3000799920.72283502251.5876321730.2000799920.5858061251.326891069517.1015.678402352480.50.50.500099990.94807232521.9495024760.400099990.84118045721.78903322940.300099990.72286021441.587677513917.2017.754044064490.60.60.6001199881.04731300592.07859950080.5001199880.9480928411.94953119370.4001199880.84120281321.789068994117.3019.3906656287100.70.70.7001399861.14114921672.18187072610.6001399861.04733224762.07862258590.5001399860.94811335661.949559910117.4020.7001774072110.80.80.8001599841.2311008212.26285480010.7001599841.14116754772.18188905160.6001599841.0473514892.078645669917.5021.7446317387120.90.90.9001799821.31827097242.32388292030.8001799821.2311184962.26286893410.7001799821.14118587852.181907376217.6022.562197435413111.000199981.40351725912.36649948410.900199981.31828818322.32389324020.800199981.23113617082.262883067217.7023.1775859718141.11.11.1002199781.48755019362.39168889881.0002199781.403534162.36650623730.9002199781.31830539392.323903559517.8023.606995652151.21.21.2002399761.57059634682.3999999521.1002399761.48756691652.39169223571.0002399761.40355106082.366512989917.9023.8606839254161.31.29948015591.2997400261.48758363942.39169557191.1997400261.57057968182.39999994371.0997400261.4871488372.391608611518.0023.9443470903171.41.19948015591.1997200281.57056301682.39999993471.0997200281.48713211352.39160525770.9997200281.40311162332.366337197318.1023.8598079657181.51.09948015591.099700031.487115392.39160190330.999700031.40309472122.36633042660.899700031.317857892.323635021318.2023.6052245042191.60.99948015590.9996800321.40307781912.36632365530.8996800321.31784067722.3236246830.7996800321.23067658882.262515346418.3023.174878949201.70.89948015590.8996600341.31782346442.32361434390.7996600341.2306589112.26250119260.6996600341.14070922692.181430648418.4022.558487283211.80.79948015590.7996400361.23064123322.26248703790.6996400361.14069089212.18141230070.5996400361.0468511412.078045152218.5021.7398149694221.90.69948015590.6996200381.14067255712.18139395220.5996200381.0468318942.07802204150.4996200380.9475798541.948812878518.6020.69409624032320.59948015590.599600041.04681264672.07799892980.499600040.94755933061.94878412970.399600040.84062141221.788138589718.7019.3830721639242.10.49948015590.4995800420.94753880691.94875537960.3995800420.84059904461.78810278320.2995800420.72220499161.586497903218.8017.7445202202252.20.39948015590.3995600440.84057667651.78806697510.2995600440.7221797811.58645250240.1995600440.58502195281.325322442918.9015.6661397347262.30.29948015590.2995400460.72215456971.58640709940.1995400460.58499177381.32526205770.0995400460.41017773460.957053581819.0012.8957424631272.40.19948015590.1995200480.58496159351.32520166860.0995200480.41013594180.956961598400019.107.6072108902282.50.09948015590.099500050.4100941450.956869604600000019.203.1895653485292.6000000000019.300

DArea AArea BKH

Basin Areas1

Weirs111

OrificesThree sheets are provided here.1. Worksheet Calculating an Elevation-Discharge Relationship for a Series of WeirsThis can be used to model a number of rectangular weirs at different levels.FOLLOW THE PROCEDURES BELOW, ENTERING VALUES IN THE YELLOW BOXES.1. Enter Parameters for 1 to 10 weirs.Weir No.12345678910Crest Elevation (m AHD)38.9939.2539.5Weir Width (m)104050Weir Coefficient1.71.71.7The lowest weirshould be placed first.2. Fill in the Required Depths in the yellow column in the table below.DepthElevationDischarge(m)(m AHD)(m3/s)038.9900.0539.040.19006577810.139.090.53758720220.1539.140.98761075330.239.191.52052622470.2539.242.1250.339.293.33738504330.3539.345.35606747090.439.397.862755450.4539.4410.76347344340.539.4914.00554216050.5539.5418.23369058510.639.5923.67704680710.6539.6429.92310179390.739.6936.84255885510.7539.7444.35974204880.839.7952.42222005370.8539.8460.99044945730.939.8970.03302282490.9539.9479.5241054635139.9989.44190074383. After Checking the Relationship, copy the two orange columns and paste this to DRAINS,copying it into an Overflow Route or Culvert component.2. Worksheet Calculating an Elevation-Discharge Relationship for a Parabolic WeirThis can be used to model a vertical curve on a road, or other weir surfaces that approximate a parabola.It is appropriate to use this for a roadway over a culvert.The curve is defined by the height above the low point, Y, at a horizontal distance X from the lowest point of the curve.FOLLOW THE PROCEDURES BELOW, ENTERING VALUES IN THE YELLOW BOXES.1. Select a Point on the Road Surface to Define the ParabolaHeight above Low Point (m)1Focus of parabola =1250References:Horizontal Distance from Low Point (m)50(Used to calculate discharges)French, R.H. (1985) Open Channel Hydraulics,McGraw-Hill, New York (page 32)2. Specify Discharge Coefficient0.9Assuming CD = 0.848 and Cv = 1.05Bos, M.G. (editor) (1976) Discharge Measurement3. Specify the Elevation of the Low Point (m AHD)38.99Structures, International Institute for Land Reclamationand Improvement, Wageningen, Netherlands4. Fill in Required Depths in the table below.(page 37)DepthElevationDischargeFrench's broad-crested weir formula is used rather than(m)(m AHD)(m3/s)of the sharp-crested weir formula.038.9900.0539.040.2156657570.139.090.86266302810.1539.141.94099181320.239.193.45065211230.2539.245.39164392540.339.297.76396725260.3539.3410.56762209390.439.3913.80260844910.4539.4417.46892631840.539.4921.56657570180.5539.5426.09555659910.639.5931.05586901050.6539.6436.4475129360.739.6942.27048837550.7539.7448.5247953290.839.7955.21043379650.8539.8462.32740377810.939.8969.87570527370.9539.9477.8553382834139.9986.26630280715. After Checking the Relationship, select and copy the two orange columns and transfer this to DRAINS.

DArea AArea BKHSlopingHorizontalComparison of Horizontal and Sloping Cylinder Areas16.716.716.72516.77516.7516.8516.816.92516.9171717.07517.117.1517.217.22517.317.317.417.37517.517.4517.617.52517.717.617.817.67517.917.751817.82518.117.918.217.97518.318.0518.418.12518.518.218.618.27518.718.3518.818.42518.918.51918.57519.118.6518.72518.818.87518.9519.02519.1001.62462643648.35164654422.285441825511.61895003863.243712308813.99106857967.685716779615.874507866412.912863620617.428425057915.678402352418.734993995217.754044064419.84313483319.390665628720.784609690820.700177407221.581241854921.744631738722.248595461322.562197435422.798026230423.177585971823.237900077223.60699565223.574350468323.860683925423.811761799623.944347090323.95307913423.85980796572423.605224504223.95307913423.17487894923.811761799622.55848728323.574350468321.739814969423.237900077220.694096240322.798026230419.383072163922.248595461317.744520220221.581241854915.666139734720.784609690812.895742463119.8431348337.607210890218.734993995217.428425057915.874507866413.991068579611.61895003868.35164654420

Orifices0000000000000000000000000

Discharge CurveElevation (m)Flow over Weir (m3/s)

PumpingWorksheet Calculating an Elevation-Discharge Relationship for a Circular Orifice or for Multiple OrificesThis calculates an elevation-discharge relationship for an orifice or group of orifices, assuming that it is submerged on the upstream side,and can discharge freely on the downstream side.FOLLOW THE PROCEDURES BELOW, ENTERING VALUES IN THE YELLOW BOXES.1. Enter Orifice Parameters.LowestOrifice No.123456ElevationElevation of Centre of Orifice (m)30.4530.73130.45Orifice Diameter (mm)75200150Orifice Factor0.60.60.62. Fill in the Required Heights above the Orifice Centre in the yellow column below.Height above3. After Checking the Relationship,LowestElevationDischargecopy the two orange columns andOrifice(m AHD)(m3/s)transfer these to DRAINS.The orifice equation is: Q = C . p/4. D2 . (2g . H)0.5(m)030.450whereQ is flowrate (m3/s),0.0530.50.0026240777C = Cc.Cv is a dimensionless contraction coefficient0.130.550.0037110063where Cc allows for the vena contracta effect and Cv for a velocity correction,0.1530.60.004545036D is the orifice diameter (m),0.230.650.0052481555g is acceleration due to gravity (9.80 m/s2),0.2530.70.0058676162H is the height of water above the centre of the orifice.0.330.750.02508775980.3530.80.0333320354C is taken as 0.6 in DRAINS for a sharp-edged orifice. Other coefficients0.430.850.0397422684may apply in special cases, as shown below.0.4530.90.04519244990.530.950.05002333310.55310.05441082520.631.050.0689563890.6531.10.07708402870.731.150.08397886870.7531.20.0901640750.831.250.09585535360.8531.30.10117046710.931.350.10618362480.9531.40.1109458725131.450.11549445411.0531.50.11985771781.131.550.12405793831.1531.60.12811305731.231.650.13203781681.2531.70.13584452951.331.750.13954362Source: Vennard, J.K. and Street, R.L.(1982) Elementary Fluid Mechanics, 6th Edition, Wiley, New York, Figure 11.291.3531.80.14314401791.431.850.1466534487The orifice equation above applies when the orifice is fully submerged on the1.4531.90.1500786549upstream side, say when H is 1.2 times the orifice radius D/2, and where1.531.950.1534255661there are no tailwater effects. This will not be correct when water level1.55320.1566994326(H - the centre level of the orifice) is below this. In this worksheet, this error1.632.050.1599049319is glossed over, assuming that errors in this range will not be significant.1.6532.10.16304625341.732.150.1661271687If the downstream side of the orifice becomes submerged, the orifice equation1.7532.20.1691510878still applies, but with H being (upstream water level - tailwater level) rather than1.832.250.1721211073(upstream water level - orifice centre level as for a free outfall. This situation1.8532.30.1750400492is not allowed for here, but this worksheet can be adapted to apply it.1.932.350.17791049441.9532.40.1807348112232.450.18351517882.0532.50.18625360852.132.550.18895196122.1532.60.19161196272.232.650.19423521752.2532.70.19682322022.332.750.1993773662.3532.80.20189895982.432.850.2043892242.4532.90.20684930612.532.950.2092802846

W1W2W3EL3EL2EL1Discharge CurveElevation (m)Flow over Weir (m3/s)000000000000000000000000000000000000000000

Pumping000000000000000000000000000000000000000000000000000

Elevation (m)Discharge (m3/s)Elevation-Discharge Relationship

TailwaterWorksheet Establishing a Pumping Curve Relationship for use with DRAINSDRAINS can model pumps using an elevation-discharge relationship in a high level outlet from a detention basin.In an overflow route out of a basin, a H v Q relationship can be defined.To obtain this, it is necessary to consider the pipe system, as shownin the diagram to the right. The pump operation is described by acharacteristic head-discharge relationship, in which the discharge rateincreases as the head decreases.In a detention basin acting as a sump storage for a pump, the pumpdischarge will increase as the basin level rises, since the heightthat the water must be raised decreases.A trial and error process must be applied to obtain an elevation-dischargerelationship from the pipe information and the pump curve obtainable frommanufacturer's catalogues.FOLLOW THE PROCEDURES BELOW, ENTERING VALUES IN THE YELLOW BOXES.1. To determine a suitable relationship, provide the information below:Entrance Loss Factor0.5Pipe Diameter (m)0.15Pump Curve:Bend and Other Loss Factor0.2Pipe Length (m)40DischargeHeadupstream and(m3/s)(m)Factor f in Darcy-Weisbach Equation0.02downstream of the pump0.01210(See Moody Diagram)0.0189Exit Loss Factor1Elevation of Discharge Point460.0238(End of Pipeline) (m AHD)0.02770.0360.03250.03342. Set out the basin levels for which discharges are to be calculated.0.03353For each elevation, determine the discharge in the third column by trial and error.The correct discharges should make the head differences in the last column close to zero.BasinTotalDischargePipeCorresp.Corresp.TotalElevationAvailable(m3/s)VelocityEnergyPumpHeadDifference(m AHD)Head (m)(to be(m/s)Loss (m)Head (m)(m)(m)varied)3790.02041.1540.4788.5208.9980.00178778537.58.50.02361.3350.6407.8508.4900.00999357163880.02611.4770.7837.2258.008-0.007782927238.57.50.02831.6010.9206.5677.4870.01302532473970.03011.7031.0415.9506.9910.008897902539.56.50.03121.7661.1195.4006.519-0.01858635764060.03221.8221.1914.8005.9910.008560282140.55.50.03271.8501.2294.3005.529-0.028728228The pump must beCalculated from(to be setselected to operate overpump curve byclose to zero)this range of heads.linear interpolation(Only possible for8 rows with Excel)3. Copy the orange columns and paste to the DRAINS pumping outlet (an overflow route coming out of the basin).BasinDischargeElevation(m3/s)(m AHD)370.020437.50.0236380.026138.50.0283390.030139.50.0312400.032240.50.0327

Tailwater109876543

Discharge (m3/s)Pump Head (m)Pump Curve

0.02040.02360.02610.02830.03010.03120.03220.0327

Basin Elevation (m AHD)Flowrate (m3/s)

Worksheet Setting Time-Varying Tailwater LevelsDRAINS allows outlets to be a free outfall or a fixed water level.By adding a channel section downstream of a pipe or channel outlet, it is possible to make the tailwater level vary with time.DRAINS allows a direct or user-provided hydrograph to be entered at a node. By varying flowrates, the corresponding water levels can be definedusing an artificial rectangular channel of 100m width and zero slope. Depths are calculated for the critical depth.FOLLOW THE PROCEDURES BELOW, ENTERING VALUES IN THE YELLOW BOXES.1. Enter the base level below. Vary the other values later if necessary.Rectangular Channel CharacteristicsWidth (m)100Base Level at Top End (m AHD)382. Insert times and the corresponding required depths in the table below.3. Transfer the data in the columns below to DRAINS as a directhydrograph at the second nodeTime AfterRequiredCorresp.Time AfterCorresp.from the outlet of the system.Start ofWaterDepthFlowrateStart ofFlowrate(The last link in the system should beStormLevel(m)(m3/s)Storm(m3/s)a 100 m wide rectangular channel(minutes)(m AHD)(minutes)0.1 m long, with nodes at each end.)0402885.40885.4540.252.251056.551056.51040.452.451200.5101200.51540.62.61312.4151312.42040.72.71388.9201388.92540.752.751427.6251427.63040.72.71388.9301388.93540.62.61312.4351312.44040.452.451200.5401200.54540.252.251056.5451056.550402885.450885.45539.751.75724.755724.76039.551.55604.160604.1When DRAINS is run, the required6539.41.4518.665518.6water levels will be specified at both7039.31.3464.070464.0ends of the dummy channel.7539.251.25437.575437.58039.31.3464.080464.08539.41.4518.685518.69039.551.55604.190604.19539.751.75724.795724.7100402885.4100885.410540.252.251056.51051056.511040.452.451200.51101200.511540.62.61312.41151312.412040.72.71388.91201388.9These numbers shouldbe large compared tothose generated bythe DRAINS model.

0000000000000000000000000

Time (minutes)Level (m AHD)

885.43774484711056.54211936861200.51312.42066426891388.86068415811427.61820876591388.86068415811312.42066426891200.51056.5421193686885.4377448471724.7197734297604.1024333671518.5672569687464.0107757369437.5464.0107757369518.5672569687604.1024333671724.7197734297885.43774484711056.54211936861200.51312.42066426891388.8606841581

Time (minutes)Calculated Flowrate (m3/s)

Dummy Channel


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