**4. Physical modeling: a case study**

*Resources of Water*

**Figure 2.**

*Model of a Typical Barrage.*

**96**

**Figure 3.**

*Model Study of Taunsa Hydro Power Project.*

(retrogression) (**Figure 3**).

In the recent past, the rationality of the massive hydraulic structure of Jinnah Barrage [4, 5] was questioned as a model study indicated that at existing conditions of water levels the formed hydraulic jump was located on the glacis only up to a discharge of 400,000 cusecs. The hydraulic performance of the barrage, under-sluices, silt excluders, and also the subsidiary weir was yet not tested at higher discharges. Mahboob [6, 7] reviewed the design of Kalabagh Barrage and he found it acceptable only after the physical hydraulic model study because the hydraulic modeling study for energy dissipation under the conditions of existing water levels pointed out that hydraulic jump over the horizontal floor was repelled by the excessive lowering of the channel bed at the downstream

The hydraulic modeling study cited here targets to examine sedimentation aspects of two cascade reservoirs on Poonch River; with the help of physical modeling and numerical simulation. A physical model of Poonch River was prepared at Nandipur Research Institute to study the sediment transport behavior [8]. After the base test, the model was used to get data for various scenarios of sediment flushing in the cascade reservoir system. The River geometry, riverbanks, hydraulic structures, crosssections, and other physical attributes of the river were prepared from a topographic

**Figure 4.** *Model Study of Poonch River Sedimentation Project.*

**Figure 5.** *Model Study of Poonch River Sedimentation Project.*

survey using AutoCAD. These files were used in HEC-RAS and BASEMENT for simulations (**Figure 4**).

Delta profile and flushing were modeled by HEC-RAS 5.0. The simulation showed that the life of the un-sluiced Gulpur HPP is about 14–15 years and that of Rajdhani is about 35 years. To enhance the life of the project, annually 4–5 days are required for flushing with an optimized discharge of about 250 m3 /s. Model verification was performed by calculating the bed topography and flushing efficiency. The results obtained through the model were consistent with bed changes, demonstrating its suitability for the regeneration of regression channels and lateral erosion (**Figure 5**).
