Hydrodynamic Investigation and Numerical Simulation of Intermittent and Ephemeral Flows in Semi-Arid Regions: Wadi Mekerra, Algeria

Abstract

Semi-arid regions are characterized by important infrequent rainfall. They often occur in early autumn and give rise to devastating floods. Flooding problems at Wadi Mekerra, located in the Sidi Bel Abbes town (Northwest Algeria), was traditionally the main concern of researchers and government officials. In this work, the magnitude of raging flood wave in the studied catchment and the principal causes are discussed. After this, we present the main hydromorphometric features and the results of numerical simulations of flood wave. This simulation is done by using finite volume shock capturing schemes. It concerns applying the first order Godunov scheme and the second order Monotonic Central scheme. The Manning roughness coefficient was used as a calibration parameter. The comparison of numerical results with observed data confirms more stability and accuracy of applied numerical schemes in rising limb phase than in the falling limb phase. These results provide information on flood forecasting and monitoring of changes in the magnitude of the flow in Wadi Mekerra. Semiaridné oblasti sú charakterizované významnými občasnými dažďami. Vyskytujú sa spravidla v jeseni a spôsobujú devastačné povodne. Povodne vo Wadi Mekerra v meste Sidi Bel Abbes (severozápadné Alžírsko) sú často problémom pre výskumníkov a vládnych úradníkov. Práca analyzuje devastačné povodne v tomto povodí. Okrem toho sa uvádzajú najdôležitejšie hydromorfomertrické charakteristiky a výsledky simulácií povodňovej vlny. Simulácia je aplikáciou Godunovovej schémy prvého rádu a Monotonickej centrálnej schémy druhého rádu. Ako kalibračný parameter bol použitý Manningov súčiniteľ drsnosti. Porovnanie simulovaných a pozorovaných údajov potvrdzuje väčšiu stabilitu a presnosť počas rastúcej vetvy prietokovej vlny, ako je tomu v klesajúcej fáze. Tieto výsledky sú informáciou o možnostiach predpovede a monitoringu povodní vo Wadi Mekerra.

Spatio-Temporal Variation Study of Physico -Chemical Parameters Characterizing Water Quality of Oued M’zab Region, Algeria

“…Industrial wastes, liquids and solids discharged without treatment of wastewater to the recipient is a danger to groundwater and the environment downstream [10][11][12]. Through this work we will try to describe the current state of water quality of the water phreatic under industrial units.…”

Estimation of flood risk thresholds in Mediterranean areas using rainfall indicators: case study of Valencian Region (Spain)

“…Valencia is the Spanish region most affected by floods, because of physical and human factors. On the one hand, it enjoys a typically Mediterranean climate, prone to intense outbreaks of rainfall towards the end of summer and throughout autumn (Millán et al 2004;Beguería et al 2009;Lopez-Moreno et al 2009;Gonzalez-Hidalgo et al 2009;Machado et al 2011), which can reach a maximum of 800 mm in a day (Gil Olcina 1989), generating dangerous flash floods, very difficult to be managed (Vinet 2008;Llasat-Botija et al 2010;Rozalis et al 2010;Korichi and Hazzab 2012).…”

Impacts of Tanning Process on ground Water Quality: a case study of M’zab valley.Algeria

“…In terms of BOD 5 and COD, [28,29] their variation indicates that the associated concentrations are signi cantly higher than the thresholds set by the standards. The results of the analyzes indicate that the coe cient of biodegrability is in the range of 0.08 < COD / BOD 5 < 0.19 in the 2 units, so the natural puri cation process is effective [30][31][32].…”