Hydraulic Assessment 29 August 2024

3. HYDRAULIC ASSESSMENT
3.1          Local Hydrology Model
The objective of the hydrologic assessment is to determine the anticipated flows from the local catchment to be used as inflows to the
hydraulic model and assess the performance of the dam spillway.

Hydrologic modelling of the catchment has been carried out using WBNM software developed jointly by the University of Wollongong, Rienco
Consulting and Balance R&D. The 2019 version has been used for this investigation with ARR2019 hydrology being used.

Modelling has been carried out for the 1% AEP storm event for a range of durations.


     3.1.1    Catchments
The dam has a catchment area of approximately 12.82 hectares. Additionally, about 1.42 hectares of the catchment discharges to a road
adjacent to the dam, with a portion of the runoff overtopping the road and flowing into the dam. The total contributing catchment area of
14.24 hectares has been included in this assessment. The catchment and impervious percentages are detailed below in Table 3.1. Fraction
impervious values have been based on aerial imagery. The dam is in Sub-Catchment D which has been shown in bold.

A catchment plan is provided in Figure 3.1.

TABLE 3.1: CATCHMENT PARAMETERS


 Sub-Catchment                 Area (ha)                                                 Fraction Impervious (%)

 A                             9.01                                                      16.38

 B                             2.27                                                      12.64

 C                             0.85                                                      28.35

 D                             1.54                                                      21.1

 E                             0.57                                                      26.84




38 BARINA COURT, POMONA I BBNE00000_0020-REP-001-0                                                                                     5