Dam Synchronisation and Flood Releases - agriwaterpedia.info

More documents

Recommendations

Info

DAM SYNCHRONISATION AND FLOOD RELEASES IN THE ZAMBEZI RIVER BASIN: ANNEX 4 OF FINAL REPORT Risk acceptance The extent and purpose for which risk zones should be established also depends on the acceptance of the risks. People might prefer to live with the risk, knowing that floods also provide benefits. Governments may accept risks for people and may not see a priority for flood risk zoning, as is evident from the situation analysis from opinions expressed in Malawi and Mozambique. The encroaching of population into the floodplains in Mozambique, continuing after the large floods at the end of the nineties and beginning of this millennium, shows that some people do not consider themselves to have other viable options. In terms of acceptance, only social surveys and stakeholder interviews can show the need for risk zoning. From the stakeholder perspectives in the section above, the use of flood risk zoning for regulation of new settlements and land use is considered difficult to implement. Flood risk zoning for regulation of new settlements A map of maximum flood extents can be useful and is a limited investment. Accurate probabilities of flooding are not currently possible, except that areas with flood frequencies higher than 1:10 years are normally locally known. Digital elevation maps and hydraulic models are generally not available, but local knowledge of historical flood levels exists and can be obtained through oral surveys. Flood risk zoning for current land use and awareness raising The example of pegging flood zones around Kariba, where a distinction is made of zones for multi-year crops and seasonally crops, can be established in different areas of the Zambezi River Basin. It needs to be noted that people have already adapted such approaches without any official flood risk zoning. Figure 7.3 shows how historical water levels are evident in the Chobe region. Flood referencing is a way of involving local communities in marking historical floods and predicting oncoming floods. In Mozambique, the locally established Flood Risk Committees (See example in Fig. 7.3) already provide the institutional set up necessary for such an approach. 58
DAM SYNCHRONISATION AND FLOOD RELEASES IN THE ZAMBEZI RIVER BASIN: ANNEX 4 OF FINAL REPORT Figure 6.3: Caprivi strip October 2010 photos show local evidence of past floods, already marking the flood levels. Flood risk zoning for insurances Flood risk zoning for insurances requires a high level of accuracy of the frequency of floods and the flood levels. Insurances would like to estimate their risk of insurance on the basis of the zoning, which will also determine the premium to be paid by the insured. This is further explained in Appendix E. Flood risk zoning for rescue and warning Maps are important in disaster management planning and need to be updated during disasters. UNOSAT in this respect delivered on the spot mapping during the floods of 2005 to 2009, using satellite imagery of real-time flood extents. Additional information on refuge routes, hospitals, higher areas could have helped to prioritize and plan rescue operations. If this is combined with flood referencing, where persons at community level are trained to forecast flooding impacts on 59
Page 1 and 2:
Doc No: FR - MR Transboundary Water
Page 3 and 4:
DAM SYNCHRONISATION AND FLOOD RELEA
Page 5 and 6:
Page 7 and 8:
Page 9 and 10:
Page 11 and 12:
Page 13 and 14:
Page 15 and 16:
Page 17 and 18:
Page 19 and 20:
Page 21 and 22: DAM SYNCHRONISATION AND FLOOD RELEA
Page 55 and 56: DAM VOLUME (x10 3 m 3 ) YIELD (x10
Page 71: DAM SYNCHRONISATION AND FLOOD RELEA
Page 97 and 98: Hydropower and other Hydropower and
Page 123 and 124:
Page 125 and 126:
Page 127 and 128:
Page 129 and 130:
Page 131 and 132:
Page 133 and 134:
Page 135 and 136:
Page 137 and 138:
Page 139 and 140:
Page 141 and 142:
Page 143 and 144:
Page 145 and 146:
Page 147 and 148:
Page 149 and 150:
Page 151 and 152:
Page 153 and 154:
Page 155 and 156:
Page 157 and 158:
Page 159 and 160:
Page 161 and 162:
Page 163 and 164:
Page 165 and 166:
Page 167 and 168:
Page 169 and 170:
Page 171 and 172:
Page 173 and 174:
Page 175 and 176:
Page 177 and 178:
Page 179 and 180:
Page 181 and 182:
Page 183 and 184:
Page 185 and 186:
Page 187 and 188:
Page 189 and 190:
Page 191 and 192:
show all

Dam Synchronisation and Flood Releases - agriwaterpedia.info

Create successful ePaper yourself

Delete template?

Save as template?