A COMPARATIVE STUDY OF LANDSLIDES AND GEOHAZARD ...

More documents

Recommendations

Info

Figure 2.7: Deep ferrisols of the Ntchenachena Area in Rumphi District which are prone to liquefaction (26.08.06). Figure 2.8: Ferrisols of the Ntchenachena Area with quartz floats which affect the shear strength of the soils. Note the formation of rills (26.08.06). 24
2.2.1.5 Climate The temperatures on the nearby Lakeshore are normally very high (over 30 0 C), but owing to the high elevation of the study area, which is at 1828m above sea level, its temperatures are relatively low. The mean maximum monthly temperature ranges from 18.5 0 C to 20 0 C and mean minimum monthly temperature ranges from 7 0 C to 10.5 0 C (GOM, 2001). The study area is one of the wettest areas in Malawi, having on average only one to two months as the dry period. Most of the rain falls between November and April. The mean annual rainfall range is over 1400mm, with the exceptional years when annual rainfall of over 2600mm is experienced (Linceham, 1972; and Figure 7.2 p.126). The main type of rain falling in the area is orographic although in summer (November to April) convectional rain falls. The types are influenced by maritime effects and the relief barrier. Warm moist air from Lake Malawi is forced to rise over the Livingstonia escarpments, resulting in rain formation (Agnew and Stubbs, 1972; and Linceham, 1972). 2.2.1.6 Vegetation The vegetation of this area is classified as Afro-montane, with scattered grass and shrubs (Figure 2.9). Common shrubs in this area include Protea, Faura saligna, and Syzigium (Section 7.3). Most of the slopes are under cultivation (Figure 7.5 p.131), and this has resulted in large scale cutting down of trees, although isolated patches of pine trees are still growing along the ridges. The rate of deforestation has accelerated in recent years mainly due to seasonal burning of the trees, bushes and shrubs for shifting (slash and burn) cultivation and hunting. These shrubs and bushes represent a degenerated type of vegetation. Along the streams, dry season cultivation is being practiced, and that has resulted in the destruction of shrubs and dambo grass. 25
Page 1 and 2: A COMPARATIVE STUDY OF LANDSLIDES A
Page 3 and 4: DECLARATION I declare that this the
Page 5 and 6: It was found that 131 landslides ha
Page 7 and 8: OPSOMMING In 2003 het ‘n aantal g
Page 9 and 10: verminder, gemeenskapsdeelname in n
Page 11 and 12: ACKNOWLEDGEMENTS I would like to ex
Page 13 and 14: us all that determination and commi
Page 15 and 16: 2.2.2.5 Climate 31 2.2.2.6 Vegetati
Page 17 and 18: 5.10.1.3 Crown Width 78 5.10.1.4 Ve
Page 19 and 20: 8.5 Cross Tabulation of Perceived C
Page 21 and 22: LIST OF FIGURES Figure 2.1a : The P
Page 23 and 24: Ntchenachena Area by goats, contrib
Page 25 and 26: Table 8.10 : Repetition of Landslid
Page 27 and 28: 1.1 Background CHAPTER ONE INTRODUC
Page 29 and 30: these factors. It also aimed at est
Page 31 and 32: Msilimba and Holmes, 2005). Norther
Page 33 and 34: 1.7 Organisation of the Thesis This
Page 35 and 36: Figure 2.1a: The Physiography of th
Page 37 and 38: To these divisions, may be added th
Page 39 and 40: Figure 2.2: Erosion surfaces of Mal
Page 41 and 42: Figure 2.3: The Geology of Malawi.
Page 43 and 44: Figure 2.4: Land use and land cover
Page 45 and 46: seasonal maximum and minimum temper
Page 47 and 48: Figure 2.5: Location of the Ntchena
Page 49: Figure 2.6: Part of the Ntchenachen
Page 53 and 54: Figure 2.10: Tobacco curing shed in
Page 55 and 56: sequence includes beds of modular l
Page 57 and 58: 2.2.2.3 Topography The Chiweta Area
Page 59 and 60: 2.2.3 Mvai/Livilivi Catchment Areas
Page 61 and 62: 2.2.3.3 Geology The rocks of the ca
Page 63 and 64: CHAPTER THREE LANDSLIDES: CLASSIFIC
Page 65 and 66: 1982). Topples have been observed t
Page 67 and 68: 3.4 Classification of Slopes In slo
Page 69 and 70: angle and hence greater values of g
Page 71 and 72: 3.6.5 Implications of Joints and Ro
Page 73 and 74: movement (Crozier, 1984). Preparato
Page 75 and 76: containing a high percentage of cla
Page 77 and 78: largest landslides occur most frequ
Page 79 and 80: Mshali, 1989; Gondwe and Govati, 19
Page 81 and 82: avalanche Abefan, Wales 21/9/1966 F
Page 83 and 84: environmental problems (Taun, 1974)
Page 85 and 86: Malawi, emphasise only the causes.
Page 87 and 88: short of the identification and con
Page 89 and 90: Ingaga et al., 2001; Msilimba, 2002
Page 91 and 92: CHAPTER FOUR LANDSLIDES INVENTORY I
Page 93 and 94: 4.2 Analysis of the Previous Studie
Page 95 and 96: 4.4 Proposed Mitigation Measures fr
Page 97 and 98: CHAPTER FIVE METHODOLOGY The curren
Page 99 and 100: Ground reference data was acquired
Page 101 and 102:
density of drainage network, and th
Page 103 and 104:
weathered. Samples were collected f
Page 105 and 106:
5.11 Soil Analyses Soil samples wer
Page 107 and 108:
5.11.1.4 Determination of Bulk Dens
Page 109 and 110:
5.11.1.8 Determination of Liquid Li
Page 111 and 112:
The questionnaire was coded for eas
Page 113 and 114:
and impacts of landslides and seeki
Page 115 and 116:
CHAPTER SIX LANDSLIDE DISTRIBUTION,
Page 117 and 118:
Ntcheu Livilivi Chiweta Lutowo 8c 2
Page 119 and 120:
distribution was evenly among SE (3
Page 121 and 122:
Figure 6.4: Mapped landslides in th
Page 123 and 124:
6.3 Classification of the Mapped La
Page 125 and 126:
Table 6.2: Landslides Classificatio
Page 127 and 128:
Table 6.4: The Determination of the
Page 129 and 130:
6.6 Discussion of the Landslides Ma
Page 131 and 132:
Catchment where the rocks hang loos
Page 133 and 134:
and the 1991 Phalombe landslides (G
Page 135 and 136:
In Ntcheu District, the Livilivi/Mv
Page 137 and 138:
Figure 6.12: Position where landsli
Page 139 and 140:
CHAPTER SEVEN ANALYSIS OF THE LANDS
Page 141 and 142:
constructed, in the Ntchenachena Ar
Page 143 and 144:
Chiweta Livilivi Mvai 3 53.29± 10.
Page 145 and 146:
was confirmed by ANOVA test (p=0.00
Page 147 and 148:
Table 7.9: Results of the Analysis
Page 149 and 150:
Table 7.11: Medium/Fine Sand Test R
Page 151 and 152:
Mvai 55.8±6. 41 1 69.2±9. 34 67.8
Page 153 and 154:
Rainfall (mm) 200 150 100 50 0 Dail
Page 155 and 156:
The landslides of the Ntchenachena
Page 157 and 158:
customary land tenure. Most of the
Page 159 and 160:
Hoek’s critical angle for sliding
Page 161 and 162:
esistance for these soils was proba
Page 163 and 164:
acting as a lubricant (Crozier, 198
Page 165 and 166:
cover of grasses and shrubs, record
Page 167 and 168:
with major structural rock weakness
Page 169 and 170:
disturbance caused by deforestation
Page 171 and 172:
Figures 7.14 and 7.15). This has pa
Page 173 and 174:
Figure 7.16: Highly weathered Chiwe
Page 175 and 176:
CHAPTER EIGHT TRADITIONAL KNOWLEDGE
Page 177 and 178:
majority of the respondents had att
Page 179 and 180:
Table 8.3: Types of Housing Distric
Page 181 and 182:
Table 8.6: Knowledge of Past Landsl
Page 183 and 184:
Table 8.9: Weather Conditions Befor
Page 185 and 186:
Table 8.11: Level of Education and
Page 187 and 188:
Table 8.13B: Age of Respondents and
Page 189 and 190:
with tertiary education were observ
Page 191 and 192:
construction during the rainy seaso
Page 193 and 194:
Figure 8.3: Degraded agricultural l
Page 195 and 196:
out an assessment of the damage. La
Page 197 and 198:
2005). The results from these studi
Page 199 and 200:
Table 8.23: Responsibility for Slop
Page 201 and 202:
This study, therefore, realises tha
Page 203 and 204:
wanted the NGOs/Government to rehab
Page 205 and 206:
difficult and also reduces the area
Page 207 and 208:
8.17.1.4 Government Policy The majo
Page 209 and 210:
noise from drums. These spirits are
Page 211 and 212:
CHAPTER NINE ANALYSIS OF LANDSLIDE
Page 213 and 214:
true for the entire East Africa reg
Page 215 and 216:
This explains why the majority of l
Page 217 and 218:
damage from landslides. In areas wh
Page 219 and 220:
embankments may result in a build u
Page 221 and 222:
continued destruction of the vegeta
Page 223 and 224:
Furthermore, future research should
Page 225 and 226:
esults have been encouraging (Mikke
Page 227 and 228:
landslides. Gender perceptions towa
Page 229 and 230:
The destruction of vegetation in al
Page 231 and 232:
stabilisation can also be achieved
Page 233 and 234:
knowledge on landslides in Malawi a
Page 235 and 236:
Badshah, A.: 1994, The Mega-Cities;
Page 237 and 238:
Briggs, J. Badri, M. and Mekki, M.:
Page 239 and 240:
Cooke, R.U and Doornkamp, J.C.: 199
Page 241 and 242:
Fairhead, J. and Scoones, I.: 2005,
Page 243 and 244:
Harlford, S. and Leonard, P.: 2001,
Page 245 and 246:
Jibson, R.W. and Keefer, D.K.: 1968
Page 247 and 248:
Ludman, A. and Koch, N.I.: 1982, Ph
Page 249 and 250:
Mwafongo, K.W.M.: 1996, Rural Devel
Page 251 and 252:
Pitty, A.F.: 1984, Geography and So
Page 253 and 254:
Tsukamoto, Y. and Kusakabe, O.: 198
Page 255 and 256:
Yamamuro, J.A and Lade, P.V.: 1998,
Page 257 and 258:
v = volume of slope material involv
Page 259 and 260:
APPENDIX 3: HOUSEHOLD QUESTIONNAIRE
Page 261 and 262:
5. Are you employed? Yes (proceed t
Page 263 and 264:
15. What are the traditional belief
Page 265 and 266:
26. Which crops were affected by th
Page 267 and 268:
36. What was the most important for
Page 269 and 270:
APPENDIX 4: DISTRICT COMMISSIONERS,
Page 271 and 272:
13 How long does it take for inform
Page 273 and 274:
6. How far have you gone with lands
Page 275 and 276:
APPENDIX 6: MULTIPLE COMPARISON TES
Page 277 and 278:
Page 279 and 280:
Page 281 and 282:
APPENDIX 9: TESTS FOR THE EQUALITY
Page 283 and 284:
Hydraulic conductivity cm/hr (>100
Page 285 and 286:
Litowo 8 Pit 9 0615288 8819034 1445
Page 287 and 288:
Mvai 2 Pit 8 0675274 8355428 1379 M
Page 289 and 290:
RAINFALL DATA FOR MVAI/LIVILIVI FRO
Page 291 and 292:
PIT 3 LUT 3 0-100 69..80 34.31 35.4
Page 293 and 294:
KASFOR PIT 1 KASFOR >100 43.06 30.9
Page 295 and 296:
PIT 4 CHIKWE 0-100 81.42 43.45 37.9
Page 297 and 298:
PIT 5 MVAI 1 0-100 51.99 36.07 15.9
Page 299 and 300:
NTCHEU FIELD DATA APPENDIX 15: RESU
Page 301 and 302:
Mchenje 167 130 5.7 4.1 Shallow ro
Page 303 and 304:
CHIWETA U1-11 Dsh (mm) Dbh (mm) H (
Page 305 and 306:
AVERAGE 125 93 5.5 3.6 LITOWO 1a-3
Page 307 and 308:
LITOWO 7a-u Dsh (mm) Dbh (mm) Mnthu
Page 309:
Mnthunu 50 Chi 1l 0615438 8819106 1
show all

A COMPARATIVE STUDY OF LANDSLIDES AND GEOHAZARD ...

Create successful ePaper yourself

Delete template?

Save as template?