Effects of land cover change on flood peak discharges and runoff volumes: model estimates for the Nyando River Basin, Kenya

Abstract

The impacts of historical land cover changes witnessed between 1973 and 2000 on the hydrologic response of the Nyando River Basin were investigated. The land cover changes were obtained through consistent classifications of selected Landsat satellite images. Their effects on runoff peak discharges and volumes were subsequently assessed using selected hydrologic models for runoff generation and routing available within the HEC-HMS. Physically based parameters of the models were estimated from the land cover change maps together with a digital elevation model and soil datasets of the basin. Observed storm events for the simulation were selected and their interpolated spatial distributions obtained using the univariate ordinary Kriging procedure. The simulated flows from the 14 sub-catchments were routed downstream afterwards to obtain the accrued effects in the entire river basin. Model results obtained generally revealed significant and varying increases in the runoff peak discharges and volumes within the bas in. In the upstream sub-catchments with higher rates of deforestation, increases between 30 and 47% were observed in the peak discharge. In the entire basin, however, the flood peak discharges and volumes increased by at least 16 and 10% respectively during the entire study period. The study successfully outlined the hydrological consequences of the eminent land cover changes and hence the need for sustainable land use and catchment management strategies.

Land use and climate change impacts on the hydrology of the upper Mara River Basin, Kenya: results of a modeling study to support better resource management

“…Model simulations suggest that any additional deforestation in the Nyangores sub-basin of the Mara River Basin will result in increased overland flow and decreased baseflow. These results confirm and bolster the findings of related efforts from the larger Mara River Basin and the adjacent Nyando River Basin (Mati et al, 2008;Olang and Fürst, 2011). The magnitude of impact appears to be greater when forest is converted to agricultural land use in comparison with grassland.…”

Tipologi Daerah Aliran Sungai Untuk Mitigasi Bencana Banjir Di Daerah Aliran Sungai Musi

“…Jenis penutupan lahan penting untuk diketahui karena berpengaruh terhadap proses hidrologi di dalam ekosistem daratan. Hal ini berbasis dari beberapa hasil penelitian bahwa perubahan penutupan lahan dan penggunaan lahan berpengaruh pada aliran sungai, debit dan potensi banjir (Olang & Furst, 2011;Bormann & Elfert, 2010). Klasifikasi penutupan lahan di DAS Musi oleh Balai Pengelolaan DAS Musi (2012) dari hasil analisis peta RBI dan peta Citra Landsat 5 TM (Basuki & Putro, 2013) memperlihatkan bahwa jenis penutupan lahan di DAS Musi bervariasi sebanyak 18 jenis (Gambar 4).…”

River flood inundation mapping in the Bago River Basin, Myanmar

“…HEC-HMS is widely applied in many water resource studies with reliable outputs (He and Croley, 2007;García et al, 2008;Chen et al, 2009;Olang and Fürst, 2011;Alaghmand et al, 2010Alaghmand et al, , 2012Joo et al, 2014;Kawasaki et al, 2013). Data were collected from various sources, mainly from the Myanmar government (Table I).…”