Civil Engineering Simulation of Catchment Modelling with Info Works CS V15.0 for Urban Drainage Design and Analysis

Transcription

1 Civil Engineering Simulation of Catchment Modelling with Info Works CS V15.0 for Urban Drainage Design and Analysis Saleh M. A. 1 *, Eziefula A. U. 2, Abubakar H. 3, Cynthia O. O. 4, Suleiman M. 5 1,2,3,4 &5 Department of Civil Engineering Technology, P.M.B 001 the Federal Polytechnic Nasarawa, Nigeria. Abstract InfoWorks CS V15.0 provides a comprehensive simulation to evaluate and develop viable sustainable alternatives on hydrological and hydraulic modelling of catchments, as well as structural performances and network incapacity of storm water and wastewater management system. Similarly, this research work having successfully evaluated the extent of flooding risk in Buckie Moray, had also come up with sustainability measures to addressing this phenomenon, via an effective utilization of InfoWorks CS V15.0 model. However, this research finding reviled a higher flooding of nodes in the relative catchments, and adopted the design of SUDS among other variable alternatives, as the most effective and sustainable option that has achieved the removal efficiency of the existing flooding within the entire catchments, as well as the successful incorporation of new sub-catchment in the entire network system. Keyword: Rainfall, Wastewater, Catchment Modelling, Simulations, InfoWorks CS, SUDS Introduction Infoworks CS V15.0 is an analytical computer based numerical modelling system in which Infoworks CS model is being developed to represent combined sewerage system (pipes, pumps manholes etc.) alongside population density, trade, as well as the volume of precipitation runoff contributing to the flow in a system. The model is however utilized to examine the level of detention storage needed in limiting any existing precipitate or storm water flowing into river or water treatment plant/works to acceptable degree of sustainability [1] [2]. Modelling is however a vital tool applicable in assessing the volume of spills, frequency as well as H 2O quality criterial for CSOs [2]. Similarly, it provides cost effective measures to CSOs to be identified and can solve structural deformation problems, including network incapacity as well as to analyse the cause for impacts on properties due to flooding alongside its effective sustainable solutions. In furtherance, it s applicable in establishing the probability for an existing network/system to accommodate the volume of flow increase resulting from new developments or any future H 2O demands [2] (Scott Arthur, 2015). InfoWorks CS programs provides H 2O facilities with an effective and unique tools in order to technically evaluate hydrological modelling within a complete urban H 2O cycles. It s however primarily built to identifying cost-effective infrastructural improvements. Similarly, InfoWorks CS accords a practical methodology in operation control and real time controls of wastewater networks, which also includes urban flooding, prediction of pollution and the prompt modelling of H 2O quality as well as sediment transportation via the entire network. It s fast and accurate in network modelling/simulations with superficial tools to undertake subcatchment take-off, including infiltration modelling. InfoWorks CS design configuration has the ability for a swift simulation of an entire network and or sub-network. Similarly, it s capable of simulating up to 100,000 nodes with complete accuracy as in the case of much smaller models [1] [3]. Application of InfoWorks CS in Civil Engineering There are quite a numbers of related InfoWorks programs available for use within the fields of civil engineering and environmental, these includes; InfoWorks CS 2D, InfoWorks Viewer, InfoWorks ICM, InfoSWMM, InfoNet and H 2OMAP SWMM. However, InfoWorks CS are applicable in the fields of Undertaking drainage and sewerage master planning/studies; assessing the impact of climatic change on urban drainage systems; effectively implement SUDS; undertakes hydraulic analysis of wastewater treatment works; capable of identifying solutions to intermittent discharges from sewerage systems (UID's, CSO's or SSO's); its applicable in flooding and pollution prediction; similarly, its used in modelling of sediments transportation and water quality analysis; combined / wastewater interceptor system design and analysis; Wastewater system assessment and management; secondary drainage and urban storm water system assessment and management; infiltration and inflow assessments; urban drainage storm runoff control and retention design and assessment; as well as urban storm water quality assessments and pollution control [1] [3]. Research location Buckie (Bucaidh) territorial was defined primarily in 1888 located in Moray Firth, Scotland coast, the United Kingdom. Buckie is the largest settlement town within Banffshire and being the third largest in Moray behind Elgin & Forres [4]. As at 2006 population estimate, Buckie encompasses male and female total population figures of Similarly, Buckie was ranked the 75 th among the populated settlements as estimated in the Scotland in the year 2006 [5]. 2098

2 Figure 1a: Part of Buckie settlement. Source: [6]. Figure 1b: Buckie settlement. Source: [6]. Critical Comperation of Models Operational Capabilities Source: [7], [8], [9], [10] and [11] Materials and Method: Step 1: Building/Constructing the model InfoWorks CS V15.0 software for installation in; At list 1GB of free space laptop/desktop computer system; An internet connection; then Import an empty file titled empty 1#1.csv (available in h:\infoworks\), after a successful installation of InfoWorks CS V15.0 software on your computer; Check-out the model empty1#1 (this is an empty default network), then name it model 1 ; Right clicking on the model 1 icon and selecting open (it s only a blank appearing space that is visible from this command); Right clicking on the white area (GeoPlan), hence open layer control ; Then select insert and browse h:\inforworks\map\. Then locate the file called Demo_road_roof_polyline.shp also Demo_road_roof_region.ship Hence, click OK which takes you back to the required GeoPlan; Right clicking on the GeoPlan to select view entire layer then, select all layers and click OK (this allows the map to be visible in which one can change to any desired colours from layer control, then properties button ) figure 3a and 3b respectively; Create the required nodes, links as well as subcatchment. This represents the sewerage system. Hence, check-out the model and then open the node grids and feed in the following data from table 1 below, hence choose nodes grid. If complete, all nodes will then be accessible on the GeoPlan. (Note: define node 8 as outfall, and similarly the rest as manholes); 2099

3 By using the new links tool, connect all the manholes as in figure 3a in red colour lines or any other preferred colour (Default colour light green). Table 1: Values of existing GL and coordinates Using the information tool, insert the links characteristics from table 2 below. Ensuring the system is set to combine. And hence, use the tool new subcatchment to creating the seven (7) subcatchment numbered 1 to 7 the same as the numbers of their nodes in which they drain into as in figure 3a below. Table 2: Links characteristics Figure 2: outfall and link (weir) With an option to splitting pipe 7.1, then click OK button and apply GL to the newly introduced manhole. Hence, delete pipe 7.1 and then substitute it with orifice. Explore the subcatchment grid and adjust all area measurements to percentage runoff area (1, 2, and 3 etc.) in the following order i.e 1-3%, 2-2%, 4-3%. This is assumed that, only a total of 10% area do contributes to the system. Hence apply infiltration which is ½ of the population flow, available in the model baseflow field in subcatchment table. Calculate flow per persons in m 3 /s from equation (1) and (3) below, to have table 5 below. Validate the entire model to ensure there s no error. Hence check in the model. Step 2: Calculating 6 x DWF Note: Assuming that the out-fall goes into WWTW which is limited to six (6) times Dry DWF so that CSO is designed in place to take care of excess fluids. Calculating 6xDWF and limiting the discharge from the catchments (model) equation (4) is considered below for both catchment 7 and 8 respectively. Step 3: Introducing limiting discharge Orifice & Weir Note: 6xDWF is however applied orifice as the limiting discharge. Therefore, check-out model 1 and rename it model 2 Introduce new manhole and call it (9) by using the new node tool as in figure 2 below Note: The fundamental theory implies; that the limiting discharge of the orifice is reached, hence, excess flows will start to back up the system. If an overflow weir is place immediately upstream of the orifice then the volume of flow over this weir will define the volume of storage required. Next step is to insert new node call it 10 as an outfall with a new link (weir) as in figure 1 above. Enter the same value of GL at node 7. The weirs characteristics are: Step 4: Completing WWG File This task WWG, allows for the effective definition of flow per persons in the catchment. Right clicking on Catchment Group 1, then create new WWG and name it WWG; Right click on this WWG, then create new Wastewater event and name it event 1 Open event 1 then click Add button, hence apply description to it, then click OK Add 145(l/day) per capital flow; The profile tab has a multiple of 1 from 00:00 23:00 this will allow for the configuration of flat profile. 2100

4 Note: these values should sum-up to 24. Hence, fill in the below dialogue box with the values as represented in it. Similarly, an event will be generated for 15, 30, , and 240 minutes duration with 20 yrs. retuned periods. Then use the winter Profile as in the below dialogue box for Rainfall Event. Hint: clicking on the results, similarly click on Graph Reports then select Multiple Report. Hence, open the existing GeoPlan, then select the expected over flow pipe. Subsequently, click and drag the simulations into the dialogue box, then click on Current for the selections. Hence, click on OK. However, this will plot a graph showing all the possible flows within the overflow pipe for the entire storms in the system as in figure 4 below. Step 5: Running Simulations In view of this, series of simulations should be explored to ascertain which case is the worst scenario, and similarly the amount of detention storage that is needed as in the dialogue box below for Scheduled Hydraulic Run. Hence, right click catchment group, then create new run group referred to as Run Group 1 Right click Run Group 1 to create new run; Use a run title, and by dragging the network titled wastewater and rainfall into the most appropriate boxes; Then use 600 minutes duration and click on run simulations. This simulation will be completed in fewer seconds; Below the run group, details for the simulation are contained in a white box. And below it are sets of green boxes, while each represents the rainfall durations; Hence, open each of these green box while using the information tool to identify the overall flow over the link (weir). However the required detention storage is defined by the peak/maximum flow in the system. Research Aim The major aims of undertaking this research work is to explore the technicality of InfoWorks CS V15.0 in order to: Overview the extent of flooding risk in Buckie during an extension for a new settlement (examine nodes flooding and its extent/percentage flooding and the expected flow of fluid over link(weir), similarly the implication this may have on the entire system); To provide for technical solution for the most sustainable option to removing and or mitigating the flood risk within the settlements and the reasons that necessitate this option. Results and Discussion Required networks The basics of this design work is to provide a modeller with an effective knowledge in InfoWorks CS V15.0 This design work had addressed the addition of new subcatchment onto already seven existing catchment in Buckie town Banffshire, Scotland the United Kingdom in order to mitigate floods from existing nodes as well as remediating flood risk within Buckie network figure 3a, 3b and figure 5a, 5b respectively. However, figure 3a and 3b represents the seven subcatchment areas within the GeoPlan/network (Buckie), as required by this research work, and in line with Infoworks CS V15.0 analytical modelling. Figure 3a: The seven sub catchments within the existing GeoPlan (Buckie). 2101

5 The use of populations for the seven subcatchment areas to determine the various infiltration rates of individual catchment in the network. Table 5 are for the initial seven (7) catchments, while table 6 contains the seven (7) catchments and the new additional sub catchment i.e catchment number eight (8) Table 5: Seven (7) Subcatchment population and infiltration rates Figure 3b: The seven subcatchment within the existing GeoPlan (Buckie). From Figure 3 and Table 3 below, are a total of 10 nodes, with Node I.D 1 7 and 9 as manholes within the pipe networks, while 8 and 10 are outfalls that discharges the storms to a Waste Water Treatment plant and into the North Sea. However, table 3 and table 4 below represent the detailed variable nodes and links characteristics as outline by this research work. Table 6: Eight (8) Subcatchment population and infiltration rates Node and pipe characteristic tables Table 3: Details of subcatchment nodes Individual nodes are connected via conduit pipe, weir and or an orifice, which are representations of the different forms of piping system. Below table are representation of the networks nodes and links characteristics designed to accommodate the expected storms. Table 4: Nodes characteristics for subcatchment from figure 1a and 1b above. Design Infiltration Rate Calculation Flow per person = 145 l/h/d same as m 3 /h/d..(1) 0.145/(24*60*60) = = x 10-6 m 3 /s Population Flow (m 3 /d) = (470*0.145) = 68.2.(2) (1309*0.145) = n p Population flow (m 3 /d) = [68.2/(24*60*60)] = = [189.8/(24*60*60)] = = n p Infiltration = [Population x Flow per person (m 3 /s)] (3) 2 470* = * = n i 2 Design Orifice Limit Discharge Calculation In order to limiting the discharge from the model as mitigation measure, the 6*DWF will be determined by using: 6 ((Population Consumption) + Infiltration + Trade Flow) which is the same as the average dry weather flow 2102

6 6 ((Population Consumption) + Infiltration + Trade Flow) Population (P) = 5299 Consumption (C) = assumed as 145 l/h/d Infiltration (i) = (1000*24*60*60) Trade Flow (T) = given as 0 in this regard figure 5a and figure 5b respectively (New subcatchment 8 with pipe networks). (4) 6 * ((5299*145 /(1000*24*60*60)) ) = m 3 /s Therefore the required Limiting Discharge value for a population of 5299 for seven (7) sub catchments = (m 3 /s) and however, including the new sub catchment eight (8), the new total population is 8265 and the required limiting discharge = (m 3 /s) Figure 5a: Additional subcatchment 8 with new node 11 New link (Weir) The provision of node ten as an outfall requires the presence of weir with a characteristics of 3m width, crest level (maod) and 0.85 as the weir coefficient is to allow for overflow that may not flow at the upstream section via the limit discharging orifice. Simulation data of seven (7) sub-catchments The graph and data for the simulation is the interpretation for the system overflow through the link (weir) i.e the crest and width of an amplitude towards their positive axis is the measure for the volume of flooding within the system as represented in figure 4 and figure 6 below. However, these are applicable when considering for effective design to overcome flood and storage structure. Similarly, these data estimates the amount in volume of fluid going through the weir in regard to the amounts of rainfall evaluated from the seven subcatchments. (Flow rate pattern passing through the weir in relation to individual rainfall) Figure 5b: Additional subcatchment 8 with new node 11 Flow increased over weir Surge infiltration exist as a result of the addition of new subcatchment within the network. However, this resulted to the increased volume of flow for the system to accommodate. Therefore, the volume of water that can flow downstream over the orifice is the same as in initial, this then requires more volume of flow that can overflow the weir via the outfall. It s obviously evident as it can be seen from figure 6 below as compared to figure 4 above. Similarly, the volume of flow of fluid above the existing weir has increased more rapidly, as a result of the new subcatchment 8 that was introduced in the network system. This phenomenon requires an immediate remediation measures to curtail and or accommodate the high volume of increased floods, or consequentially, the system will experience the risk of over flooding which will subsequently leads to damages and loss of physical properties/structures within the network. Figure 4: flow rate pattern passing over the weir prior to addition of new subcatchment Adding subcatchment 8 to the existing 7 sub-catchments in the network However, the Addition of sub catchment 8 requires an additional pipe network to collect fluid over the catchment area and to prevent over flooding within the entire network Figure 6: Flow over weir after the addition of new subcatchment 8 within the network system 2103

7 Over flooding of nodes Following the introduction of new subcatchment 8 in the network, the amount of flooding has increased drastically at node 3, 4, 6 this is approximately eight time the initial flooding volume over the nodes. Similarly, node 11 from the new subcatchment is experiencing higher volume of flooding as in figure 6. However, prior to the addition of the new subcatchment 8 within the network, the amount of flood occurs only at node 3, 4 and 6. These can be evaluated from table 7 below. In furtherance, figure 6 and table 7 respectively shows flood increased after the addition of subcatchment 8 within the system. However, this has eventually lead to adverse higher increased flooding on all the nodes in the network, and apparently node 11 experiences much higher flooding due to direction of flow, congestion of pipes, topographical nature of the network and sediments transportation within the entire network system. with the presence of existing structures as well as utility facilities that exists within the entire network system. So also the initial option may not improve significantly on the flooding risk as required. Theoretically this is a cheap method that may not be technically effective in solving the flooding risk within the network system. Table 7: Flood prior to the addition of new subcatchment 8 in the network Figure 7: The required pipe length within node 11, 4, 6 and 7. Table 8: Flood increased resulting from the addition of new subcatchment 8 in the network Available options for reducing the existing flood risk within the network From the over flooding phenomenon, there exist alternatives to reducing the flooding risk from Buckie settlement (entire network) these options includes: to increasing the entire diameters of pipes in the network or to increase the pipe connecting node 11 via 4, 6, 7 and to drain at an out fall, node 10. Alternatively to introduce SUDs (sustainable urban drainage system) pond within the newly added subcatchment 8, which will be linked to an outfall to drain into Burn of Buckie River flowing in the direction of North Sea. Similarly, adding a combine storage tank within pipe network 4 and 11 is another open alternative to mitigating the flooding risk. Increasing the diameters of pipes within the network Increasing the diameter of pipes across node 11, 4, 6 and 7 from figure 7 below as an option for reducing the flooding risk, however this alternative is capitally intensive in terms of replacing all the existing pipes within these terrains, not even the entire network system which is both technically and financially not advisable, as this is termed; the worst case scenario ever. Similarly, these options will prove abortive Adding combine storage tank in between node 4 and 11 However, this process has some positive effect on the storm flooding in accordance to the following test; by increasing more and more, the size of storage tank between node 4 and 11 figure 8a, however no flooding from the tank will be experienced, but a significant drop on flooding from system is however recorded. Technically, this is not the convenient alternative to undertake, for there is the need to have an extremely large tank which will eventually require lager space as a result of its depth limit i.e 3meters in order to attaining proper flow due to topographical slope as in figure 8b. Alternatively, is to relocate the storage tank position towards the steep slope which will allow increase in its depth, nevertheless this will prove abortive as a result of the existing developmental structures. However this process is effective but technically complex in its general nature, within the proposed environment and the possible geological structure of the soil alongside already existing utility facilities underground. Figure 8a: Adding a storage tank between node 4 and

8 Figure 8b: cross-section over proposed storage tank from figure 8a above Figure 9c: Cross section over SUDS and Burn of Buckie river outfall from figure 9b above Viable option for accommodating and remediating flooding risk in the network However one of the choosing option to mitigate this over flooding phenomenon is by adding sustainable urban drainage system pond, within the new subcatchment with an outfall connected via pipe as illustrated in figure 9a and 9b below. The presence of the SUDS pond will collect and drain water from the subcatchment, thereby reducing the volume of over flooding water and subsequently discharges the water via a conduit drainage system (out fall) into Burn of Buckie river. However this process will be more effective and most sustainable to remediate the presence of over flooding risk within the entire network system as illustrated in figure 9a and 9b respectively. Similarly this option will cater as well as accommodate future storms and developmental structures within the environment for sustainability regenerations. However, this section across the conduit pipe figure 9c, outlines a connection from the SUDS to drain into Burn of Buckie river which shows the pipe is laid on suitable gradient that will allow for easy drainage and the volume of flow of water is controlled by an orifice of 0.05m 3 /s to regulate the volume and the velocity of the discharge, which may result to over flooding of the river. Figure 9d is the section across the SUDS in respect to the sub catchment 8 GL. While figure 9e provides a detailed cross section of flow on the existing orifice in the outfall direction. Figure 9d: Cross section over SUDS pond Figure 9a: SUDS pond design in sub catchment 8 with an out fall into Burn of Buckie River Figure 9b: Enlarged section of the designed SUDS pond in sub catchment 8 with an out fall into Burn of Buckie River flowing in the direction of North Sea Figure 9e: Cross section of flow over orifice 0.05m 3 /s 2105

9 Reducing flow passing over the weir Flow over the weir has reduced, this can be analysed by the plot of graph for flow passing over the weir before and after introducing subcatchment 8, as well as after the introduction of designed SUDS with an orifice of 0.05m 3 /s. However, from the graph in figure 10a and 10b, it can be deduced that for all rainfall records there have been drastic reduction on flow passing over the weir, this then implies that only lesser volume of combine system fluid flow with a steady velocity are emptied into any existing natural channel, river or the North sea. be deduced that, the entire flooding from the nodes as on figure 10b and table 10 below, has shown a drastic removal/minimization of more than two third (2/3) of the initial volume of flood experienced on node 6, as well as the complete removal of flooding from the entire nodes: 3, 4 and 11 in the network i.e table 10 when compared and contrast to table 9, prior to the designing of a SUDS pond as remediation measures to reducing the volume of flooding risk. Therefore, as a result of this analytical research outcomes, the preferred most effective and sustainable option will remain to apply this design (SUDS pond) in physical construction process and as in design principle flooding can be tolerated ones in 20 years forecasting. Table 9: Result indicating flooding increased in the network Figure 10a: Flow rate pattern over weir prior to the design of SUDS pond in the network Table 10: Result indicating flood removal efficiency in the network Table 11: The summaries of advantage and the advantages of SUDS as applicable in urban drainage system Figure 10b: Flow rate pattern over weir after the design of SUDS pond in the network Prove for the removal of the flooding risk Considering the data on table 9 below, the volume of flooding as a result of the addition of subcatchment 8 from figure 9a, and figure 10a above has increased, and similarly it can now 2106

10 Conclusion Buckie master plan requires an additional subcatchment within its designed network in order to mitigate the existing flood risk, this has been a crucial phenomenon militating its settlers. However several alternatives were made available for the flood remediation measures via Infor-Works CS simulation model for urban drainage system, and these includes; addition of a combined storage tank between node 4 and 11, or to increasing the diameter of the conduits within the entire network system, or the pipes that runs from node 11, 4, 6, and 7 respectively. But consequentially these are not effective and sustainable options, because it s however capitally intensive as it will require a deep excavation of new and existing drainage structures, that will result to the destruction of several existing residential structures and utility facilities underground within the required network. However, the fourth option is to design a SUDS pond within sub catchment 8. Apparently, this has proven to be most suitable, sustainable and technically effective remediation option chosen. In lieu of these scenario, this analytical research work has successfully designed a SUDS pond with an orifice of 0.05m 3 /s to help in accommodating the additional catchment storms as well as to mitigating over flooding of the receiving river into which the water is being discharged regularly as an outfall. Similarly, this is the only option that have achieved the removal efficiency of flooding risk in all the existing nodes as well as the entire network system (catchments), so also it has reduced more than two third of the flooding within node 6 from M20-15 flood volume of 82.1 m 3 to 30.5 m 3 and similar M with flood volume of 89.2 m 3 to 13.2 m 3 respectively. In conclusion, this method as adopted in mitigating the flood risk, had drastically reduce/eliminates the volume of flooding experienced in the network as well as flow over weir. And however it has succeeded in minimizing the presence of wastewater discharging into any natural or artificial channel for environmental sustainability. Nomenclature Acknowledgement Our sincere appreciation and acknowledgement goes to our noble Dr Scott Arthur from the School of the Built Environment (Civil engineering and Water resources) Heriot- Watt University Edinburgh Scotland the United Kingdom, for his utmost contributions to have proposed these problems and the technical support to addressing these phenomenon in all ramifications during the periods for the preparation to this research work. References [1] Innovyze (2011) InfoWorks CS Technical Review [Online] Available at: products/infoworks_cs/infoworks_cs_technical_revie w.pdf [Accessed 23th November 2015]Buckie settlement (2015). Google Satellite Maps. [Online] Available at: [Accessed 30th November 2015] [2] Scott Arthur Dr. (2015) Urban Drainage Analysis InfoWorks CS v Heriot Watt University Edinburgh, United Kingdom. [3] Innovyze (2015) InfoWorks CS Overview [Online] Available at: infoworks_cs/ [Accessed 23th November 2015] [4] Ainmean-Àite na h-alba - Gaelic Place-Names of Scotland - Database (2011). [Online] Available at: p?id=1767 [Accessed 30th November 2015] [5] National Record of Scotland (2015). [Online] Available at: theme/population/population-estimates/special-area- population-estimates/settlements-and-localities/mid- 2006/list-of-tables [Accessed 29th November 2015] [6] Buckie settlement (2015). Google Satellite Maps. [Online] Available at: [Accessed 30th November 2015] [7] Wallingford Ltd (2008) Infoworks CS [Online] Available at: orks_cs/ [Accessed 3rd December 2015] [8] DHI Ltd (2015) MIKE URBAN [Online] Available at: EURBAN.aspx [Accessed 13th December 2015] [9] USEPA (2007) SWMM. Storm Water Management Model User s Manual Version 5.0, EPA/600/R- 05/040 [10] USEPA (2014) SWMM [Online] Available at: tm [Accessed 10th December 2015] [11] Lockie T. (n.d) Catchment Modelling Using SWMM. Hydraulic Analysis Limited [Online] Available at: 0File&Folder_id=135&File=lockie_t.pdf [Accessed 27th November 2015] 2107