Numerical simulation of groundwater flow in the Peshawar intermontane basin, northwest Himalayas

Yousafzai, Asim; Eckstein, Yoram; Dahl, Peter

Numerical simulation of groundwater flow in the Peshawar intermontane basin, northwest Himalayas | Simulation numérique des écoulements souterrains dans le bassin d’entremont de Peshawar (Nord-Ouest de l’Himalaya) Simulación numérica del flujo subterráneo en la cuenca intermontana de Peshwar, noroeste de los Himalayas Simulação numérica do fluxo de água subterrânea na bacia intramontanhosa de Peshawar, noroeste dos Himalaias 喜马拉雅山西北部Peshawar山间盆地的地下水流数值模拟

2008

Yousafzai, Asim | Eckstein, Yoram | Dahl, Peter

The hypothesis that abnormal fluid pressure is generated in basins under tectonic compression is tested. The study site, between the Main Karakoram Thrust (MKT), Main Mantle Thrust (MMT), Main Central Thrust (MCT), Main Boundary Thrust (MBT) and Salt Range Thrust (SRT) in northwest Pakistan, is experiencing a tectonic compression of 90 MPa. The Peshawar basin is a broad, oval depression comprising a thick sequence of lacustrine, deltaic and fluvial sediments overlain by loess and alluvial deposits dated at 2.8–0.6 Ma. It is surrounded by the Precambrian and Tertiary intrusive and metamorphic rocks on the north and sedimentary rocks of Paleogene and Neogene to the south. The basin was divided into four hydrostratigraphic units for numerical simulations using the three-dimensional finite-element model FEMWATER within groundwater modeling system (GMS) ver. 5.1. Simulated pressure head data have been compared with the field measurements of hydraulic heads. Transient simulations indicate that topography alone is not sufficient to induce the pressure heads observed in the field, generating consistently positive residuals 0.98–2.90 m over the topography-driven flow. The residuals disappeared after inclusion of the elastic properties of the four hydrostratigraphic units in the model, suggesting the effect of tectonic compression.

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