Details

Autor(en) / Beteiligte

• Nasri, S

Titel

Characteristics and hydrological impacts of a cascade of bench terraces on a semi-arid hillslope in central Tunisia

Ist Teil von

• Hydrological sciences journal, 2007-12, Vol.52 (6), p.1134-1145

Erscheinungsjahr

2007

Link zum Volltext

Quelle

Taylor & Francis Journals Auto-Holdings Collection

Beschreibungen/Notizen

• The benching of hillslopes in Tunisian semi-arid regions is intended to reduce soil erosion, store water runoff and enhance infiltration on hillslopes. The hydrological impact of bench terrraces remains unknown; therefore, that of a cascade of bench terraces built in June 1997 on a 14.48 ha hillslope in the Ousseltia region of central Tunisia was evaluated. Accurate topographic measurements were used to determine precise characteristics and hydrological effects for each contour ridge. In June 2006, the total retention capacity of the cascade was 2535 m super(3). In nine years, the channels uphill of the bench terraces have lost 31% of their initial storage capacity. Each year, approximately 171 t of sediments are retained uphill of these bench terraces. Before the bench terraces were set up, the runoff coefficient for a rainfall event of 64 mm was 65%. In the first year after introducing the terraces, the runoff coefficient for a similar event was 20%. After nine years, the runoff coefficient is 38%. Moreover, if all the runoff area uphill of the benches were ploughed, the runoff would be reduced to zero for a 64 mm rainfall event, even after nine years. Thus, bench terraces do significantly reduce runoff, erosion and sediment transport on this engineered hillslope.