PhD Thesis Emmanuel Obeng Bekoe - Cranfield University

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Figure 4.4 Annual Streamflow data for Manhia and Nsawam……………….83
Figure 4.5 Land Use map of Densu Basin (Year 1990) ……………………..85
Figure 4.6 Land Use types for the Mosiac of thickets & grass with/without
scattered trees……………………………………………………….87
Figure 4.7 Typical land use types showing the (a & b) moderately dense
herb/bush with scattered (15/trees/ha) canopy with herb and bush
cover………………………………………………………………… 88
Figure 4.8 Soils of Ghana compared to soils of Southern Africa …………. 91
Figure 4.9 Soils of Southern Africa (source: University of KÖln 2005)…… 92
Figure 4.10 Vertical clay distribution models for southern Africa ……………94
Figure 4.11 Monthly Mean Temperatures for Koforidua (1965-1980)………100
Figure 4.12 Sunshine Duration data for Koforidua and Accra (1967-1980) …101
Figure 4.13 Wind speed data at Koforidua……………………………………..102
Figure 4.14 Mean monthly Relative Humidity for Koforidua…………………..102
Figure 4.15 Sub-catchments of the Densu Basin…………………………….105
Figure 5.1a Response of Baseflow to changes in soil parameters…………114
Figure 5.1b Response of Baseflow to changes in soil parameters cont’d…115
Figure 5.1c Response of Baseflow to changes in crop parameters………..115
Figure 5.2a Response of Streamflow to changes in soil parameters ……...115
Figure 5.2b Response of Streamflow to changes in soil parameters cont’d116
Figure 5.2c Response of Streamflow to changes in crop parameters……..116
Figure 5.3 Comparison of Baseflow (bf) and Streamflow (sf) for most
sensitive parameters………………………………………………116
Figure 5.4 Response of changes in COFRU parameter to Baseflow and
Streamflow…………………………………………………………117
Figure 5.5 Comparison of streamflow parameters for Apan (apan) and
Hargreaves (Har) methods for the most sensitive parameters 118
Figure 5.6 Calibration and validation calendar for ACRU modelling ……..122
Figure 5.7 Calibration procedure adapted from Adjami et al. (2004)……..125
Figure 5.7b Graph of calibration appraisal statistics, showing PBIAS and NSE
at any calibration point …………………………………………....127
Figure 5.8 Daily calibrated simulated streamflow at Manhia in the lumped
mode……………………………………………………………… 128
Figure 5.9 Weekly calibrated simulated streamflow for the Densu river in the
lumped mode at Manhia ………………………………………….129
Figure 5.10 Daily validated simulated streamflow in the lumped mode at
Manhia………………………………………………………………131
Figure 5.11 Weekly validated simulated streamflow for the in lumped mode at
Manhia ……………………………………………………………..131
Figure 5.12 Flow path of the Densu Modelling……………………………….136
Figure 5.13 Comparison of observed and simulated daily flows for the
calibration and validation periods of the semi distributed model at
Nsawam………………………………………………………….....137
Figure 5.14 Comparison of observed and simulated weekly flows for the
calibration and validation periods of the semi distributed model at
Nsawam……………………………………………………………...138