4. THE SCOPE OF THE ASSIGNMENT
4.1 Work Scopes
Member Development Plan Update
• Collect member municipalities most updated development plans and population projection. Have conversations with member municipalities’ planning and engineering departments for information clarification.
• Apply engineering judgment and justification to verify member’s development plan and population projection and determine the reasonable timing, development area, and associated population for future flows used in the model.
• Provide sewage catchment maps as basis of the model.
Base model review, update, and calibration
• Review, check, and update the Base Model.
• Verify the base sanitary flow, including domestic flows and ICI flows
• Analize dry weather flow patterns and identify average and Peak dry weather flows.
• Analize wet weather flow, including inflow and infiltration characteristics and peak wet weather flow for the events of 25 year 24 hour rainfall and 5 year 4 hour rainfall.
• System deficiency identification
• Base Model calibration and reporting
Future flow projection, dynamic model simulation, deficiency identification, and sewer upgrade options
• Apply verified member development plan and population projection to the future flow simulation.
• System deficiency identification
• Provide system upgrade solutions and timing and high level cost estimates
Deliverables
• Base Model of existing sanitary sewer system
• Base model development report
• Summary of population and municipality’s development projection and consultant’s justification-based recommendations to the model application.
• Model analysis results for future scenarios to identify system deficiencies and develop upgrade options.
• Using colour coded maps to show modelling results, including pipe utilization percentages, water level in manhole.
• Using maps to show existing and future sewer catchments.
• Model transfer logger (ARROW to provide the empty logger).
• Hydraulic-based upgrade options and recommendations.
• Final Report
4.2 Requirement
Model Development
• Use of Mike Urban as the modelling platform for the model development.
• Model infrastructure should include gravity sewers, pump stations, manholes, and all valves on sewers if applicable.
• Use 1:25 year 24 hour and 1:5 year 4 hour rainfall events to simulate the wet weather conditions
• Analysis horizon is up to 2055.
• Recommend the method for population and municipalities’ development projections and discuss with the ARROW prior to proceeding.
Model Development Report
The report should at least document the following information
• List of all sources of data (including physical, geographic, meteorological, flow or engineering data etc) used by or linked to the model
• Catchment areas illustrated on maps
• Catchment layer description
• List and maps of all locations of catchment connections to the regional trunk
• Domestic sewer flow generation method, including the list of various per capita loading rates for catchments
• Commercial sewage generation method, including the list of various area-based loading rates and scaling factors
• Diurnal pattern used for model development
• Groundwater Infiltration (GWI) generation method, including various loading rates and patterns (provide a detail list)
• Rainfall dependent Inflow and Infiltration (RDII) generation method (provide a detail list summarize all parameter values for each catchment)
• Detail description and explanation of the model calibration results
• Future flow monitoring recommendations
• Assumptions for the model development
• A list of filenames of components, and file content
• Version of software used
• Model use limitations
Final Report
A final report will be required to summarize all study results and conclusions, including at least the following information
• A summary of modifications made to loading against the Based Model
• A summary of modifications made to infrastructure against the Base Model
• List of all sources used by or linked to the model
• Locations of catchment connections to the regional trunk if changed
• Domestic sewer flow generation per capita loading rates for new catchments
• Commercial sewage generation loading rates and scaling factors for new areas
• Diurnal pattern used for model development if changed
• Groundwater Infiltration (GWI) generation method, including various loading rates and patterns if changed (detail list)
• Rainfall dependent Inflow and Infiltration (RDII) generation method if changed (detail list)
• Detail description and explanation of the model simulation results
• Assumptions for the model analysis
• A list for scenario management details, such as the purpose of the analysis, filenames of components, and their content
• Version of software used
• Model use limitations
• Situation results and sewer system deficiency identification
• Ratios of PWWF to PDWF and PWWF to ADWF for existing and future scenarios.
• Storage volumes if storage facilities are required
• Alternative solutions description and recommendations for future upgrade plan
• Use asset IDs rather than model nodes to describe model scenarios, stimulation results, and results analysis in the report
• Completion of Model transfer log (template to be provided by Arrow)
