8.2.2 Data Collection and Model Parameters
Several sources of data were used in the development of the StormNet models:
- Survey information provided by AGM was used to develop existing catchments to each drain
- Field inspection of the drain was conducted to verify condition of the drain (refer to Appendix D for photo inventory)
- OMAFRA soils mapping as well as orthophotography were used to establish CNs.
Figures 6.1 and 8.1 illustrate the drainage areas contributing to the Marentette Mangin Drain for existing and future conditions respectively. Tables 8.3 and 8.4 summarize the areas and calculated CNs of each sub-catchment for the existing and future conditions respectively.
Input parameters were selected using MTO design charts and based on a review of topographic information, soil mapping, and land use coverage. Table 8.1 summarizes the parameters used in StormNet hydrology model.
Table 8.3 – Summary of Existing Drainage Area to the Marentette Mangin Drain
| Catchment ID Exist Mar Man | Drainage Area 20.13 | Weighted Average CN 63 |
Table 8.4 - Summary of Proposed Drainage Area to the Marentette Mangin Drain
| Catchment ID | Drainage Area (ha) | Weighted Average CN |
|---|---|---|
| Area 1 | 0.92 | 93 |
| Area 2 | 1.19 | 86 |
| Area 3 | 1.74 | 82 |
| Area 4 | 2.03 | 78 |
| Area 5 | 9.65 | 92 |
| Area 6 | 1.25 | 86 |
| Pond 5 | 0.92 | 84 |
| Exist Mar Man | 15.42 | 63 |
8.2.3 Model Results
The 6-, 12- and 24-hour durations of the 2- through 100-year return period events were simulated using the MTO District 1 IDF curves to identify the most stringent storage requirements. The 24-hour 100-year event was found to require the highest peak flow rate control and runoff volume storage. Table 8.5 provides a comparison of the existing and future peak flow rates for the Marentette Mangin Drain at the Lambton Street storm sewer inlet.