Inundation Issue and Management in a Nepal Terai District STUDY REPORT July, 2005 Submitted by: Pravin K. Ghimire/CMS Nepal To: Nepal Water Partnership/ Jalsrot Vikas Sanstha Anamnagar, Kathmandu 1.0 INTRODUCTION The Study on Inundation Issue and Management in a Nepal Terai District has been initiated by the Jalsrot Vikas Sanstha (JVS) with an overall objective of facilitating water policy and strategy development at relevant levels. This Draft Final Report has been prepared according to the contract agreement made on 22 March 2005. Department of Water Induced Disaster Prevention (DWIDP) has completed a study namely Study of River Systems in Terai from Jhapa to Siraha Districts (SRSJSD) in July 2004. The objectives of SRSJSD included: a) gather basic technical and social data and information on the rivers and drains that cross Indo-Nepal border in the study districts; b) assess the historical flood events and their impacts on both local communities and natural regimes of those rivers; c) gather information on the encroachment and human intervention into the natural regimes of those river systems on the Nepalese side and their observed effects in chronological order; and d) analyze and compile those data and info rmation and present them in Geographical Information System (GIS). As a study output of SRSJSD, inundation prone wards were delineated in GIS environment along with watershed area of the rivers crossing the Indo-Nepal border from Jhapa to Siraha Districts. The study showed that the total average area, which comes under regular submergence1 due to monsoon flood, is 26,085 ha. Out of this, 10,395 ha in Jhapa, 6,705 ha in Morang, 2,900 ha in Sunsari2, 3,035 ha in Saptari and 3,050 ha in Siraha come under submergence regularly. In terms of river, Biring, Kankai and Ratuwa in Jhapa district have been identified as the rivers with substantial risk of inundation. As a next step to the study, suggestions were put forward by the DWIDP to delineate inundation dema rcation area within those wards to come up with more accurate information in regard to inundation area. In addition, the SRSJSD has recommended that local level institutions should be strengthened and environmental aspects should be considered to manage the inundation problems in the study area effectively. This study is a follow up of the SRSJSD and thus has been formulated in line with the suggestions provided by the DWIDP and the recommendations outlined by the SRSJSD. In this perspective, this study has worked out more precise inundation area in Jhapa district3. Within the district, the study has focused on three major rivers namely Biring, Kankai and Ratuwa as they were found causing significant inundation compared to other rivers. For better analysis and presentation, a GIS based thematic maps of inundation prone area has been prepared. Further, the study has also examined the strengths of the existing local level institutions and recommended measures for their enhancement to effectively deal with inundation problems within the study area. In addition, it has also identified general environmental impacts of inundation. Analysis of such systematically gathered and compiled technical, social, institutional, and environmental data and information on the concerned rivers can contribute in timely and effective solutions to the inundation problems in the country and along the Indo-Nepal border. The broad objective of this study is to contribute in operationalization of national water strategy, policy and plans with regard to water induced disasters (WID), especifically in 1 Regular submergence refers to case of inundation with frequency 1 in 1 to 3 years. 2 The Koshi River was not included in the study. 3 Jhapa district has been selected for the study because SRSJSD showed that it has bigger area susceptible to inundation compare to other districts . Inundation Issue and Mangement in a Nepal Terai District Page 1 relation with inundation. It will also help further forge dialogue among the stakeholders on the WID and, subsequently, assist in informed decision making in realizing the efficiency objective. This report comprises of two volumes. This main report (Volume-1) starts with the introductory part in Chapter 1 followed by Chapter 2 with the information on the existing national scenario, bilateral issues, policy and planning support, description of the study area etc. Chapter 3 describes objectives and scopes of the services followed by Chapter 4 consisting the adapted methodology. Chapter 5 covers the findings of the study in terms of technical, institutional, environmental and social description of the studied rivers and their inundation-affected area followed by Chapter 6 with conclusions and recommendations. The report also comprises of five annexes. Checklists and the questionnaires used for the study are presented in Annex-1. Annex-2 presents reference coordinates of the inundation prone area obtained from the field. Results of calculation regarding discharges of various return periods of those rivers are presented in Annex-3. Information from the field in relation to the action plans and constitutions of main committees in each of these rivers are presented in Annex-4. Photographs of important places are presented in Annex-5. Volume-2 of the report comprises of relevant maps including ward level maps, topographical maps and GIS based maps with the inundation area delineated on them. Inundation Issue and Mangement in a Nepal Terai District Page 2 2.0 NATIONAL CONTEXT 2.1 General Water and risk is a cross-cutting theme that encompasses many institutions as well as communities. Water, which is the most cherished boon of nature, can also be the cause of disastrous calamities to life and property. Therefore, the judicious harnessing, utilization and protection of this resource is of paramount importance for human survival, well being, and economic progress. Nepal has many river systems stretching from the Himalayas to the Ganga tic plains. The average density of 0.3 km per sq km of more than 6,000 river systems in Nepal expresses the closeness of these channels. The rivers from the territory of Nepal are drained to India. Such rivers include large snow-fed and medium sized rivers like; Bagmati, Kamala, Karnali, Gandaki, Sapta Koshi, West Rapti, etc. The average annual runoff from all the rivers is estimated to be over 220 billion m3 (BCM). The dominant feature of Nepal’s water resources is that though the country occupies only about 13 percent of the total drainage area of the Ganges River, it contributes as much as 70 percent in the lean season and some 45 percent of its average annual flow to the Ganges River. This way, Nepal being rich in water resources offers a fertile opportunity to enhance the quality of life of numerous people by exploiting these resources. Despite lot of benefits, these river systems are often the cause of risks and vulnerabilities that apply to mountain communities as well as low land inhabitants in Nepal. Poverty and vulnerability to water induced hazards appear to be closely linked in the context of Nepal. Several water induced disasters including inundation, landslides, debris flows, droughts, Glacial Lake Outburst Flood (GLOF) and epidemics of water borne diseases are common phenomena in Nepal. Given the country's geo-climatic condition, such disasters may be expected to occur more often and at any time and in any place, in the light of Global Climate Change, especially the Global Warming. 2.1.1 Some Facts and Figures Majority of the inundation affected communities in Nepal live in the marginalised river area. These rivers are generally rainfed, and originate from the southern face of the fragile mountain chain. The fragile geological structure of the terra in in combination with torrential monsoon rains and intense tectonic activity result in high sedimentation in the rivers. The shifting nature of the river courses in the plain areas due to large quantities of sediment deposition causes river bed aggradation and inundates farmland and settlements. In the past, numerous people have lost their lives and many of them have been displaced. According to the available data, flood occurred during 30 July to 2 August 2003 alone killed 244 persons injuring 310 persons and badly affecting 9, 063 families throughout the country. Available data indicate that about 12,000 landslides/slope failures occur each year in Nepal. Similarly, catastrophic event of flood disaster including inundation occurred in 23 August 1993 left a mournful reminiscence in Nepalese heart killing 1,048 people and affecting total of 553,000 people throughout the country. Likewise, Available records from 1995 to 2000 reveal that, on an average, 250 people have lost their lives annually in such disasters. Inundation in the Study Area The Biring River Inundation Issue and Mangement in a Nepal Terai District Page 3 According to the SRSJSD, seven village development committees (VDC), namely Saranamati, Surunga, Dangibari, Ghailadubba, Chakchaki, Rajgadh and Gherabari, are regularly affected by inundation due to overflow in the Biring River. Event of inundation occurs once in two to three years. Each event is associated with 1 to 4 cases of submergence during June to August lasting for 12 to 24 hours. Total average area that comes under submergence regularly is about 2,585 ha. Total affected households and population comes to be 3,525 and 17,930 respectively (excluding the inundation area of Gherabari VDC, which was excluded due to security reasons)4 The Kankai River The SRSJSD showed that seven VDCs, namely Mahabhara, Shivganj, Tagandubba, Kumarkhod, Surunga, Pancganchi and Saranamati, are regularly affected by inundation in the Kankai River's surroundings. Event of inundation occurs once in two years. Each event is associated with 1 to 3 cases of submergence during June to August lasting for 5 to 8 hours. Total average area that comes under submergence is about 2,100 ha with average submergence depth of 1.00-1.25 m.