The return of the water - IUCN

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11 11.1 Introduction Economic Justification of Additional Floodplain Re-inundation By Lucy Emerton The hydrological and ecological rehabilitation of the Waza Logone floodplain, through re-inundation, is an important element of the Waza Logone project. To date the project has already accomplished two pilot flood releases, which have led to demonstrable recoveries in floodplain flora and fauna. The local people welcomed the pilot flood releases, because they profited from the increased productivity of the floodplain. A number of different release options had been worked out by the project. It was intended that further restoration of the previously inundated area would be achieved by constructing engineering works that allow flood releases from Lake Maga and its associated water courses. The implementation of any of these options requires a considerable financial input. A study was therefore carried out to estimate the economic returns of additional floodplain re-inundation to justify investments in flood release measures in order to safeguard the hydrological, ecological, biodiversity and socio-economic benefits of the Waza Logone floodplain. This implied that only those benefits were valued that were believed to be sustainable. The study excluded unsustainable resource utilisation activities, even where these are made possible (over the short-term) by flood release. It also did not value illegal resource utilisation, e.g. hunting and grazing in the Waza National Park. The study focused on valuing the so-called on-site benefits and costs of flooding that would accrue inside the floodplain region and would be received by the floodplain population. Although re-inundation may result in a number of off-site economic impacts, such externalities were not the primary focus of this study. Finally, the study concentrated on the incremental values of re-inundation over the current situation of reduced flooding. It therefore looked at the additional economic values that will result from flood release - it is concerned with changes in floodplain economic benefits and costs that are directly caused by re-inundation. It should be emphasised that figures reached are a preliminary indication of the broad magnitude of the benefits and costs of flood release, and should not be taken as exact or indisputable values. They relied on very limited original data collection and on the information and reports available at the time within the Waza Logone project. Much of this data was approximate or incomplete. 11.2 Options for re-inundation Building on work originally carried out in 1983, four options for flood release in the Waza Logone region were identified in 1994: a pilot release, an almost complete restoration, and two intermediate options (Wesseling et al., 1994). A preliminary cost-benefit analysis concluded that the pilot release and large-scale re-flooding options could be profitable, whereas small-scale re-flooding was not economically attractive. Pilot releases of floodwater from the Logone River were subsequently implemented in 1994 and 1997. These modified and opened the channels of two watercourses that connected the Logone to the Logomatya, and that had been blocked by the SEMRY works: the Petit Guruma in 1994, and the Areitekele in 1997. These pilot releases resulted in an annual increase in the area flooded of around 200 km 2 (see Chapter 10). The return of the water led to a marked recovery in the number 105
The Return of the Water of water birds and certain mammals, increase in fish production, improvement and extension of pasture, and changed agricultural opportunities (the replacement of rain fed millet with flood-fed rice and sorghum). In 1999 a revised proposal for re-inundation was made, which updated the three options first presented in 1994 (IUCN, 1999b). This proposal focused on two main zones for release, one from Lake Maga, which usually has excess water in August and September; and a second zone from the area immediately to the north of the rice cultivation area of the irrigation scheme. The proposal consisted of three different components: Options X, Y and Z, each allowing a different level of additional flows and level of floodplain restoration (Table 11.1; Figure 11.1). It should be noted that none of these re-inundation options would reduce the surface area of irrigated fields that are actually cultivated in the SEMRY scheme (Wesseling et al., 1994). 106 Total area reflooded, including pilot areas (km 2 Option Additional flow (m ) 3 Total flow /s) (m 3 % restoration ) in average year Good year Average year Poor year X 215 250 90 916 867 646 Y 165 200 71 839 687 532 Z 115 150 50 645 479 291 Table 11.1 Reinundation options. Original flooded area Reduced flooding after SEMRY scheme Pilot flood release area Maximum flood release option Figure 11.1 Extent of proposed flood releases. From IUCN, 2002.
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IUCN - The World Conservation Union
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The designation of geographical ent
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Table of Contents Foreword vii Cont
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Foreword This book tells the story
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Contributors Dr. Mike Acreman, Head
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from the Atlas de la Province de l
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List of Tables 1.1 Major floodplain
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List of Plates 1.1 Different views
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1 1.1 Floodplains Introduction By P
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Introduction Rainfall in the Sahel
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species of ungulates, such as korri
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From its inception, the Waza Logone
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Part II The Receding Water
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The Return of the Water tonnes to 4
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The Return of the Water that the re
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3 Consequences of the Dam and the D
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eduction in flooding (Drijver and M
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3.3 Socio-economic consequences Con
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4 The Wider Context By Sun Yan Evan
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Africa. A third migration route to
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The Wider Context The geographical
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5 Hydrology of the Waza Logone Area
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variable, the extent, depth, durati
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Hydrology of the Waza Logone Area C
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The Return of the Water brought to
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The Return of the Water 1997). The
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The Return of the Water dam, the pe
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The Return of the Water 1948; Ngog
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The Return of the Water into the bu
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Part IV Living with the Seasons
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The Return of the Water While the f
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The Return of the Water Most of the
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The Return of the Water which the f
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The Return of the Water from € 0.
Page 79 and 80: The Return of the Water The Musgum
Page 81 and 82: The Return of the Water check their
Page 83 and 84: Plate 1.2 Kob antelopes at the Mahe
Page 85 and 86: Plate 7.2 Seasonal movements of pas
Page 87 and 88: Plate 7.4 Fishing cannals in the Lo
Page 89 and 90: Plate 7.7 Big fish are only caught
Page 91 and 92: The Return of the Water staple food
Page 94 and 95: 8 Conflicts and Conflict Management
Page 96 and 97: Conflicts and Conflict Management i
Page 98 and 99: Conflicts and Conflict Management i
Page 100: Part V The Intervention
Page 103 and 104: The Return of the Water for the Exi
Page 105 and 106: The Return of the Water both techni
Page 107 and 108: The Return of the Water (IUCN 2000a
Page 109 and 110: The Return of the Water 9.5 The Waz
Page 111 and 112: The Return of the Water of the part
Page 114 and 115: 10 The Waza Logone Project in Actio
Page 116 and 117: The Waza Logone Project in Action F
Page 118 and 119: The Waza Logone Project in Action F
Page 120 and 121: The Waza Logone Project in Action f
Page 122 and 123: follow to obtain permits, and also,
Page 124 and 125: started by painting in red trees or
Page 126 and 127: The Waza Logone Project in Action
Page 128 and 129: The project maintained relations wi
Page 132 and 133: Although it is impossible to effect
Page 134 and 135: Economic Justification of Additiona
Page 142 and 143: Figure 11.5 Composition of incremen
Page 146: Economic Justification of Additiona
Page 150 and 151: 12 Tools and Practices for Floodpla
Page 152 and 153: of the 1994 and 1997 pilot flood re
Page 154 and 155: Tools and Practices for Floodplain
Page 156 and 157: A major output from the study was a
Page 158 and 159: Step 10. Monitor, evaluate and adap
Page 160 and 161: 5. Assess the impacts of options.
Page 162 and 163: Introduction 137
Page 164 and 165: Introduction From this premise the
Page 166 and 167: Introduction One of the most promis
Page 168 and 169: Introduction reorganisation of the
Page 170 and 171: Introduction Improving the effectiv
Page 172 and 173: Map 6.1 Satellite images showing se
Page 174 and 175: Map 6.3 Positions of two elephants
Page 176 and 177: Introduction Beauvilain, A. 1981.
Page 178 and 179: Introduction Gash, J.H.C., C.A. Nob
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Introduction Moritz, M., P. Scholte
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Introduction communities’ and ind
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The return of the water - IUCN

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