Page 250 - AJWEP-22-4

Mohamed and Katambara

Figure 1. Location of the study area
Note: Red line on the map represents location of the study area of the side drain along the road section.

a study demonstrated the effectiveness of HEC-RAS
in simulating urban stormwater behavior, while two
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other studies applied the model to assess riverine
flooding and cross-sectional changes in Indian rivers. 31,32
Similarly, calibrated models by Samal et al. validated
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HEC-RAS’s accuracy in replicating real-world flow
scenarios. Building on this robust foundation, the
present study utilizes HEC-RAS to assess the adequacy
of side drains along the TANZAM Highway, focusing
on their capacity to manage runoff and sediment under
dynamic hydraulic conditions.
Figure 2. The channel bed profile of the side drain
along the Simike–Nzovwe highway section 2.2.1. Specific energy

The specific energy of flow in an open channel is a
maintenance planning and system optimisation. 27,28 crucial factor in understanding flow behavior, especially
Recent advancements in HEC-RAS have enhanced during transitions between subcritical and supercritical
its capability to model stormwater pipe networks and regimes. It is defined as the sum of the potential and
manage mixed flow regimes, allowing application in kinetic energy of the flow, and is given by Equation I.
both urban and rural drainage contexts. For example, This equation helps determine critical flow conditions,
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Volume 22 Issue 4 (2025) 242 doi: 10.36922/AJWEP025190146