Small dams provide water storage, flood protection and ground water recharge for water scarce country like Pakistan. However, damming up water may pose some risks to population dwelling downstream the dam. Hence it is vital to study the impact of dam failure beforehand. Different types of Physical and Numerical modeling are used for it. The availability of high end computers, Digital Elevation Models and multi‐dimensional (1D,2D &3D) numerical solvers, have enabled water resource professionals to perform hydrological and hydraulic modeling efficiently and accurately.

In this study a two‐dimensional unsteady flow modeling was performed using HEC‐RAS for Aripir Dam, a small dam to be constructed in arid region of Sindh. Hydrograph of 100‐year return flood period was produced using HEC‐HMS. Dam Overtopping and piping breach were modeled. Four scenarios (i) sunny day dam break, (ii) rainy day dam break, (iii) no breach (flood peak routing) and (iv) dam Break with piping breach, were modeled.

In overtopping cases breach parameters were calculated using MacDonald et al method. Piping breach modeled in (iv) triggers as reservoir level reaches HFL of Case (iii). Flood propagation transects were digitized after analyzing 1‐hour flood extents of Case (ii) and Case (iii). Different results include maximum flood inundation maps, flood propagation maps, population at risk maps, Depth x Velocity map to identify hazardous and life‐ threatening zones, were produced. Model also predicted breach hydrograph for each case (i) 17642.11 (ii) 24154.38 (iii) 11664.99 and (iv) 18535.84 cusecs. Rainy day breach is predicted to be most disastrous event.

Access the Conference Proceedings Paper on ASCE Library 

Small dams provide water storage, flood protection and ground water recharge for water scarce country like Pakistan. However, damming up water may pose some risks to population dwelling downstream the dam. Hence it is vital to study the impact of dam failure beforehand. Different types of Physical and Numerical modeling are used for it. The availability of high end computers, Digital Elevation Models and multi‐dimensional (1D,2D &3D) numerical solvers, have enabled water resource professionals to perform hydrological and hydraulic modeling efficiently and accurately.

In this study a two‐dimensional unsteady flow modeling was performed using HEC‐RAS for Aripir Dam, a small dam to be constructed in arid region of Sindh. Hydrograph of 100‐year return flood period was produced using HEC‐HMS. Dam Overtopping and piping breach were modeled. Four scenarios (i) sunny day dam break, (ii) rainy day dam break, (iii) no breach (flood peak routing) and (iv) dam Break with piping breach, were modeled.

In overtopping cases breach parameters were calculated using MacDonald et al method. Piping breach modeled in (iv) triggers as reservoir level reaches HFL of Case (iii). Flood propagation transects were digitized after analyzing 1‐hour flood extents of Case (ii) and Case (iii). Different results include maximum flood inundation maps, flood propagation maps, population at risk maps, Depth x Velocity map to identify hazardous and life‐ threatening zones, were produced. Model also predicted breach hydrograph for each case (i) 17642.11 (ii) 24154.38 (iii) 11664.99 and (iv) 18535.84 cusecs. Rainy day breach is predicted to be most disastrous event.

**[Access the Conference Proceedings Paper on ASCE Library](https://doi.org/10.1061/9780784483466.018)** 

Dam Breach Flood Inundation Modeling For Aripur Dam, Sindh, Pakistan

Created in 1999, the Environmental & Water Resources Institute (EWRI) is the recognized leader within ASCE for the integration of technical expertise and public policy in the planning, design, construction, and operation of environmentally sound and sustainable infrastructure impacting air, land and water resources.

[Paper Proceedings](https://doi.org/10.1061/9780784483466)

Conference DOI: https://doi.org/10.26226/m.6329c39b68fb0e00131f77d2